SPF information are TXT records which have been additional to DNS Zones so that you could specify the servers from which emails might be despatched. If you already have a connector that's configured to deliver messages out of your on-premises Group to Microsoft 365 or Office 365 (as an example, https://landenghwkw.get-blogging.com/26609788/the-definitive-guide-to-google-cloud-install