Outlook 365 Signature Setup: Complete Guide for 2026

Which Outlook 365 version are you using?

Before you set anything up, figure out which version you’re in. The steps are different for each one, and mixing them up is the most common reason people can’t find the signature settings.

One important thing to know: signatures don’t sync between these clients. Classic Outlook stores signatures locally in %AppData%\Microsoft\Signatures. New Outlook and OWA store them in the cloud via Microsoft 365. Outlook mobile has its own separate store. That means if you set up a signature in one place, it won’t appear in the others automatically.

Setup for classic Outlook desktop

This is the most feature-complete option. Classic Outlook’s signature editor supports rich HTML, inline images, and full formatting. Here’s the full process:

Options explained

The Signatures dialog has a few settings that aren’t obvious:

• New messages vs Replies/Forwards: These are separate assignments. Most people set a full signature for new messages and a shorter one (or none) for replies. Having your full 6-line signature on every reply thread gets cluttered fast.
• E-mail account dropdown: If you have multiple accounts in Outlook — like a personal and work account — signatures are per-account. Switch the account in this dropdown to set up signatures for each one separately.
• Multiple signatures: You can have more than one signature and switch between them manually in the compose window. Create them all in the Signatures dialog and give them clear names. In the compose window, go to Insert → Signature to pick a different one for a specific email.

If your signature uses images, read the Outlook HTML signature guide before you paste anything. Classic Outlook handles image embedding differently from other clients and has specific quirks around base64 images.

Setup for new Outlook

New Outlook (the web-based version Microsoft has been rolling out as the default since late 2024) has a simpler interface but fewer options than classic Outlook. Here’s how to set up your signature:

The roaming signatures feature is what links new Outlook and OWA together — a signature you create in one will appear in the other. But it won’t appear in classic Outlook. For more on this, see the Outlook roaming signatures guide.

Setup for Outlook Web Access (OWA)

OWA is the browser-based version of Outlook at outlook.office.com. It shares signature storage with new Outlook — if you set up a signature in OWA, it will also appear in new Outlook and vice versa.

OWA has better HTML support than classic Outlook’s signature editor because it runs in a browser. Images, links, and table-based layouts all work well. For a full Outlook-compatible signature with the right HTML structure, the Outlook-compatible signature guide explains exactly what CSS and HTML to use.

Setup for Outlook mobile (iOS and Android)

Outlook’s mobile app has the most limited signature support of all the clients. You get plain text only — no HTML, no images, no bold or italic. It’s a separate setting from everything else and doesn’t sync to desktop.

For more detail on mobile-specific limitations and workarounds, see the Outlook mobile signature guide.

Admin setup: deploying signatures for your organization

If you manage Microsoft 365 for your company and need to deploy a consistent signature to all users, you have three main approaches. Each one works differently and has real tradeoffs.

Option 1: Exchange transport rules (server-side injection)

Transport rules run on Microsoft’s servers and append a signature to every outgoing email, regardless of which client the user sends from. Users don’t need to do anything — the signature is added automatically.

Option 2: Group Policy (classic Outlook only)

Group Policy can pre-populate signatures on domain-joined Windows PCs running classic Outlook. You copy the signature files (.htm, .rtf, .txt) to each user’s %AppData%\Microsoft\Signatures folder via a GPO login script, or use the Office ADMX templates to set signature registry keys. This only works for classic Outlook on domain-joined machines — it has no effect on new Outlook, OWA, or Outlook mobile.

Option 3: PowerShell per-user deployment

For Microsoft 365 environments without on-premises Group Policy, PowerShell via Exchange Online lets you set the roaming signature for each user. This pushes the signature into Exchange Online, which means it appears in new Outlook and OWA. Classic Outlook users won’t see it unless they also use new Outlook.

PowerShell script for bulk signature deployment

This script connects to Exchange Online and sets a personalized HTML signature for every user in your organization. It pulls the user’s display name and email from their mailbox and inserts them into the signature template.

Prerequisites

# Install the Exchange Online module if you haven't already
Install-Module -Name ExchangeOnlineManagement -Scope CurrentUser

# Connect to Exchange Online
Connect-ExchangeOnline -UserPrincipalName [email protected]

Bulk deployment script

# Get all mailboxes in your organization
$mailboxes = Get-Mailbox -ResultSize Unlimited -RecipientTypeDetails UserMailbox

foreach ($mailbox in $mailboxes) {

    # Get display name and email address
    $displayName = $mailbox.DisplayName
    $email = $mailbox.PrimarySmtpAddress

    # Get job title from Active Directory / Azure AD
    $adUser = Get-User -Identity $mailbox.Identity
    $title  = $adUser.Title
    $phone  = $adUser.Phone

    # Build the HTML signature
    $signatureHtml = @"
<table cellpadding="0" cellspacing="0" border="0" style="font-family:Arial,sans-serif;font-size:14px;color:#1a1a1a;">
  <tr>
    <td style="padding:0;">
      <strong>$displayName</strong><br>
      <span style="color:#555555;font-size:13px;">$title</span><br>
      <span style="color:#555555;font-size:13px;">$email</span><br>
      <span style="color:#555555;font-size:13px;">$phone</span>
    </td>
  </tr>
</table>
"@

    # Plain text fallback
    $signatureText = "$displayName`n$title`n$email`n$phone"

    # Push to Exchange Online (New Outlook + OWA)
    Set-MailboxMessageConfiguration -Identity $mailbox.Identity `
        -SignatureHtml $signatureHtml `
        -SignatureText $signatureText `
        -AutoAddSignature $true `
        -AutoAddSignatureOnReply $false

    Write-Host "Set signature for $displayName ($email)"
}

Write-Host "Done. Signatures deployed to $($mailboxes.Count) mailboxes."

For the full Outlook 365 signature reference — including all HTML elements that render correctly in every version of Outlook — see Outlook 365 email signatures.

Common issues and how to fix them

These are the problems that come up most often with Outlook 365 signatures.

Tips for teams: create once, deploy everywhere

If you manage email signatures for a team — whether it’s 5 people or 500 — the core problem is always the same: signatures need to look consistent across everyone, but each person is using a different combination of Outlook clients and devices.

The approach that works best for most teams is to centralize the design but distribute the implementation. Here’s what that looks like in practice:

For the full picture on managing signatures across an organization, see the email signature for teams guide.

Related guides

Frequently asked questions