How do I create a BIMI record?

Publish a TXT record at:

default.\_bimi.yourdomain.com

with fields such as:

v=BIMI1 l=https://media.yourdomain.com/logo.svg a=https://media.yourdomain.com/vmc-cert.pem

For self asserted BIMI without a VMC use an empty authority tag like this: a=;

The l= tag points to the SVG logo. The a= tag points to the VMC certificate.