The most common use for a TXT file or record related to OWA is to prove you own the domain so you can use it for professional email.
: Use the Exchange Management Shell to set the download hostnames: powershell owa domain.txt
: Send an email with an inline image to an OWA user. Right-click the image and select Copy Image link —it should point to your new download domain. Summary of DNS Record Values Record Type Host / Name TXT @ or blank MS=msXXXXXXXX Verify Domain Ownership CNAME owa mail.domain.com Alias for easier OWA access The most common use for a TXT file
Set-OrganizationConfig -DownloadDomains @{Add="attachments.yourdomain.com"} Use code with caution. Summary of DNS Record Values Record Type Host
If you are managing an on-premises Exchange Server, "Download Domains" are used to isolate attachments and inline images for security (preventing script execution in OWA).
Add a TXT record to your DNS settings (e.g., at GoDaddy or Namecheap) using the value provided by Microsoft (e.g., MS=msXXXXXXXX ).
: Navigate to the Microsoft 365 Admin Center under Settings > Domains .