Agent WranglersDeliverability Recommended
Use a steady sender identity
Send from the same From name and address on the same domain every time, and use a reply address people can actually reach.
How to do it
Pick one From address per kind of mail, such as receipts@mail.example.com. Avoid noreply addresses where replies are useful, as reply-to explains. Never put another company's domain in From, such as gmail.com. Free mailbox domains publish strict DMARC policies, so that mail fails.
How to check
The last 100 messages of each kind use one From address on your own domain.
For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/deliverability/steady-identity.