How to Change Signature in Outlook: Desktop, Web, Mobile

Few things are more aggravating than sending a business email from your phone, then catching a rookie mistake in your signature two minutes later — while it’s already sitting in someone’s inbox. The good news: changing your Outlook signature isn’t complicated. The catch: the steps differ depending on whether you’re on desktop, web, or mobile. Microsoft runs three separate signature systems, and each one hides its settings in a different place.

Primary Platforms: Desktop, Web, Mobile · Official Source: Microsoft Support · Common Path: File > Options > Mail > Signatures · Web Path: Settings > Accounts > Signatures · Variants Covered: 365, Mac, iPhone, Android

The table below summarizes the exact path to signature settings on each Outlook platform, sourced from official Microsoft documentation.

How do I change my signature in Outlook email?

The answer depends on which Outlook version you’re running. Microsoft has been transitioning users from “Classic Outlook” to “New Outlook” — and the two versions use completely different menu paths. If you’re not sure which one you have, open Outlook and look for a Settings gear in the top toolbar. If you see it, you’re on New Outlook. If not, you’re on Classic.

Desktop app steps

For New Outlook desktop, the path is Settings > Accounts > Signatures. Once there, you can edit an existing signature or create a new one. You can also choose whether to apply the signature to new messages only, to replies and forwards only, or to both — via checkboxes that Microsoft provides on the same screen. Users can format signatures with font, color, and styles using the built-in editor.

For Classic Outlook for Windows, go to File > Options > Mail > Signatures. This opens the Signatures dialog where you can create, edit, and set defaults. Note a quirk Microsoft flags: newly created signatures are not automatically added to the message you’re currently composing — you must insert them manually to that specific email.

New Outlook toggle

Microsoft is gradually moving all desktop users to New Outlook. If your organization has not yet enabled this, Classic Outlook remains your default. You can manually switch to New Outlook via the Try the new Outlook toggle in Classic, but this is optional. Either way, your signature settings stay isolated to that specific version — switching versions does not carry your signature over.

How to set up an email signature in Outlook?

Setting up a signature means two things: creating it and deciding when it should appear. Both steps happen in the same Signatures dialog on desktop, or the same Settings screen on mobile and web. You don’t need to create a signature from scratch every time — once it’s saved, you can reuse it.

Creating a new signature

In Classic Outlook, click New or open the blank signature field, type your name, title, contact info, and any legal disclaimers you need. Use the mini formatting bar to add links, images, or styled text. For advanced layouts — think multi-column tables or company logos — Microsoft recommends building the design in Word, copying it, and pasting it into the signature editor. Pre-designed Word templates for signatures are available for download from Microsoft and can be customized and pasted directly.

Setting as default

In both New Outlook and Outlook on the Web, the settings screen lets you pick a default signature for new messages and a separate default for replies and forwards. These are independent choices — you might want a full signature on new emails but a shorter one on replies. In Classic Outlook, the same dialog (under E-mail Signature tabs) lets you set both defaults from two dropdown menus. The implication: you can tailor your signature presence depending on context, which helps maintain professionalism without cluttering short replies.

How to change signature in Outlook Web?

Outlook on the Web hides its signature settings under a longer path than the desktop versions. The good news: it’s still a straightforward three-click process.

Gear icon path

Click the gear icon in the top toolbar. Then select Settings > Accounts > Signatures. Your signature lives in the Signature text box on this page. Edit it directly, then use the checkboxes to choose whether it applies to new messages, replies and forwards, or both. Click Save when you’re done.

Compose and Reply settings

The same screen lets you control your default font, size, and color for new emails — separate from your signature. If you’ve set a signature here, you can also manually insert it while composing a message by going to the Message tab and clicking Signature. Note: users with both Outlook desktop and Outlook on the Web must create signatures in both products separately — they share nothing.

How to change signature in outlook app?

The Outlook mobile app runs its own signature system that doesn’t talk to the desktop or web versions. If you want the same signature everywhere, you’ll need to set it manually on your phone or tablet — and accept that rich formatting won’t survive the transfer.

Mobile app Android

On Android, open the Outlook app and tap your profile picture or the hamburger menu. Go to Settings > Mail > Signature. Tap the signature field to edit it. Note: the mobile app supports text only — no images, no sampled templates, and limited font and color options compared to desktop versions.

iPhone steps

On iPhone or iPad, open the Outlook app and tap the menu icon (three horizontal lines). Then tap the gear icon for Settings. Scroll to the Signature row. Tap it to enter your text. Like Android, the iOS app gives you a plain text field — rich formatting, images, and templates are not supported. Desktop signatures can be copied and pasted into this field, but the formatting may not display the same way.

Why am I not able to edit my signature in Outlook?

Several things can lock you out of editing a signature in Outlook. The most common: read-only mode triggered by an administrator who has deployed a global signature through Microsoft 365. In that scenario, your personal signature settings may be greyed out because a company-wide rule is already injecting a disclaimer at the admin level.

Outlook 365 fixes

First, check whether your organization uses Microsoft 365 admin controls. Global signatures are created via Exchange > Mail flow > Rules > Apply disclaimers — this is an admin-level setting that pushes signatures to all outgoing mail. When this is active, personal signatures need to be disabled in both the Outlook application and Outlook web to prevent duplicates. If you’re a regular user (not an admin), ask your IT department whether a global signature policy is in place.

Reset signature

If you’re not under a global policy and still can’t edit, try clearing the existing signature, saving, closing Outlook completely (not just minimizing), and reopening. Then re-enter your signature. For Classic Outlook, the Signatures dialog sometimes caches old values — a full restart of the application clears this. If the field still appears locked or greyed out, repairing the Office installation through Control Panel > Programs > Microsoft 365 > Change > Quick Repair often resolves permission issues with the Outlook data file.

How to add a signature automatically to new emails?

Outlook can append your signature automatically — you don’t need to remember to insert it each time. The mechanism is the same across New Outlook, Classic, and Outlook on the Web: set a default signature for new messages in your signature settings, and every new compose window will add it automatically.

Default signature settings

In New Outlook: Settings > Accounts > Signatures, use the two dropdown menus to pick a signature for new emails and a separate one for replies and forwards. In Classic Outlook: File > Options > Mail > Signatures, set the defaults under E-mail Signature. In Outlook on the Web: Settings > Accounts > Signatures, pick your defaults using the same checkbox and dropdown controls. The key limitation: newly composed messages get the default automatically, but messages you forward or reply to require the second dropdown to be set — it controls that behavior independently.

Signature management across Microsoft 365 organizations

Organizations with Microsoft 365 Business or Enterprise plans can deploy signatures organization-wide using admin controls — no individual setup required.

Global signature deployment

Admins create global signatures through the Exchange admin center via Mail flow > Rules > Add a rule > Apply disclaimers. This injects a standardized HTML signature into all outgoing emails regardless of what the individual sender has configured. When this is active, Microsoft recommends disabling personal signature defaults in individual Outlook apps to prevent double signatures — one from the personal setting, one from the global rule.

Cross-platform considerations for teams

If your team spans desktop, web, and mobile users, the practical approach is to set global rules at the admin level for consistency and brand compliance, then allow individual mobile users to add a short text-only contact block as a secondary signature. This gives you the company logo and legal disclaimer centrally managed, while individual users retain a personal touch on replies sent from phones.

“Select Settings > Accounts > Signatures. Choose your signature, edit it, and decide whether it applies to new messages, replies, and forwards.”

— Microsoft Support (official documentation)

“Email signatures do not synchronize between Outlook desktop and Outlook mobile app. Users must set signatures in each product separately.”

— YouTube – Outlook Email Signature Sync Guide (video walkthrough)

For business users who switch between desktop, web, and phone throughout the day, the practical reality is straightforward: treat each Outlook platform as its own environment. Set your full, formatted signature on desktop or web — wherever you have the most control — and use the mobile app for quick replies where a simple text contact block won’t embarrass you. If brand consistency is non-negotiable, involve your IT team to push a global signature rule through Microsoft 365 admin, then let individual users handle only the mobile layer manually.