Once you sign up your domain for Google Workspace, you will have to change its MX records to start using their email services.
You can do that from Site Tools -> Domain -> DNS Zone Editor. Under the Manage DNS Records section remove any existing MX records.
Make sure to remove all the existing MX records before proceeding.
Then create new MX records from the MX tab. The MX records are:
Priority Destination
1 ASPMX.L.GOOGLE.COM
5 ALT1.ASPMX.L.GOOGLE.COM
5 ALT2.ASPMX.L.GOOGLE.COM
10 ALT3.ASPMX.L.GOOGLE.COM
10 ALT4.ASPMX.L.GOOGLE.COMLeave the Name and TTL at their default values and input only the Priority and Destination fields.
After that, edit the domain’s SPF record and add the following:
include:_spf.google.comThe SPF record is the TXT one that starts with “v=spf1”. You can add the above line right before the “~all” part.
The changes require up to 72 hours to propagate and take effect. After that, your mail will be handled exclusively by Google Workspace.