Step 1: Create One TXT Record
Important that you create only one TXT record for SPF.
Step 2: Append The New Office 365 Values
If you already have an SPF record, then you should append the new office 365 values to do it, instead of creating a new one.
Step 3: Ensure The Syntax Is Correct
After you update the SPF record, you should check to make sure that the syntax is correct by using the tools:
- SPF Record Tools
- SPF Surveyor
- Dig Web Interface