A BIMI record defines how a logo can appear in the customer's inbox.
BIMI is a new standard that allows your brand logo to appear on your email in your customer's inbox. This helps improve brand recognition and trust with your users. A spam email pretending to be from your domain will not display your logo. This is not yet widely supported and is invite-only, but it doesn't hurt to prepare because it will probably be available someday.
To implement BIMI, there are number of prerequisites.
You must implement SPF, DKIM and DMARC and you must have your DMARC policy set to "quarantine" or "reject".
You must have a registered trademark with a recognized government agency. The USPTO trademark process takes many months and at least $250, so you may want to get started early.
You must purchase a Verified Mark certificate from a Certificate Authority. This will be similar to an SSL certificate. It will not be cheap, and as of the writing of this article there are no CAs that are issuing certificates. It's invite only.
You must create an SVG version of your logo saved in a specific format.
You must create a DNS TXT record pointing to your logo and certificate.
You can do the last two steps if you want, but it won't do anything until the previous steps are implemented. Here is how:
First, create an SVG of your logo and save it in the "SVG P/S" format. This is a new format that is not yet widely supported, but you can download a conversion tool on the BIMI website.
You then need to create a DNS TXT record with the name "default._bimi.example.com" and include information about your logo and certificate.
To learn more about BIMI and other email authentication mechanisms, please read our article on Best Practices for Sending Email.