Setting up an SPF Record in Apple Mail
I send all my emails using Apple Mail, both on my Apple desktop, my iPhone and my iPad. I use, variously, a gmail account, a BT account and my website's server but they all are generated within Mail. In the last few weeks, however, I've noticed any email I send using gmail gets bounced back if directed to a gmail address. I'm told this is because I need to set up an SPF record, but where do I set it up? And how? Technoclot here, so please explain as to an artistic but not terribly clued up ten year old.
iMac 21.5″ 4K, macOS 13.4