- Connect to the Office 365 account using the Office 365 REST API. You will need to authenticate using OAuth2 and obtain an access token.
- Once you have obtained the access token, you can use the REST API to get the user’s profile information, including their email address.
- Create an HTML file that contains the signature. You can use HTML tags to format the signature as you want it to appear.
- Upload the HTML file to a public location, such as a SharePoint site or a public website.
- Use the REST API to update the user’s email signature with the URL of the HTML file. You can use the Set-MailboxMessageConfiguration API to do this.
- Once the signature is set, you can use the REST API to verify that it has been set correctly.
Here is an example of what the script might look like in PowerShell:
# Connect to Office 365
$ClientId = “<Your app client ID>”
$ClientSecret = “<Your app client secret>”
$TenantId = “<Your Office 365 tenant ID>”
$Username = “<Your Office 365 username>”
$Password = “<Your Office 365 password>”
$AuthUrl = “https://login.microsoftonline.com/$TenantId/oauth2/token“
$ResourceUrl = “https://outlook.office365.com“
$ApiVersion = “v2.0”
$AuthBody = @{
grant_type = “password”
client_id = $ClientId
client_secret = $ClientSecret
username = $Username
password = $Password
resource = $ResourceUrl
}
$AuthResponse = Invoke-RestMethod -Uri $AuthUrl -Method POST -Body $AuthBody
$AccessToken = $AuthResponse.access_token
# Get user profile information
$ProfileUrl = “https://graph.microsoft.com/$ApiVersion/me“
$ProfileHeaders = @{
Authorization = “Bearer $AccessToken”
}
$ProfileResponse = Invoke-RestMethod -Uri $ProfileUrl -Headers $ProfileHeaders
# Create HTML signature file
$SignatureHtml = @”
<html>
<body>
<p>Insert your signature here</p>
</body>
</html>
“@
# Upload HTML signature file to SharePoint
$SharePointUrl = “https://<Your SharePoint site URL>/Documents/Signature.html”
$SharePointHeaders = @{
Authorization = “Bearer $AccessToken”
“Content-Type” = “text/html”
}
Invoke-RestMethod -Uri $SharePointUrl -Headers $SharePointHeaders -Method PUT -Body $SignatureHtml
# Set email signature
$SignatureUrl = “https://<Your SharePoint site URL>/Documents/Signature.html”
$SignatureApiUrl = “https://graph.microsoft.com/$ApiVersion/me/MailboxSettings/messageRules/0/actions/appendHtmlBody“
$SignatureHeaders = @{
Authorization = “Bearer $AccessToken”
“Content-Type” = “application/json”
}
$SignatureBody = @{
Order = 1
ActionType = “appendHtmlBody”
ActionData = @{
ContentLocation = $SignatureUrl
}
} | ConvertTo-Json
Invoke-RestMethod -Uri $SignatureApiUrl -Headers $SignatureHeaders -Method PUT -Body $SignatureBody
# Verify email signature
$VerifyUrl = “https://graph.microsoft.com/$ApiVersion/me/messages“
$VerifyHeaders = @{
Authorization = “Bearer $AccessToken”
“Prefer” = “