The official solution is to reference a Verified Mark Certificate (VMC) in your BIMI record. This handles all of your email addresses at once. Your logo needs to be registered as a trademark, and you will need to purchase a VMC from DigiCert or Entrust. The cost to register a trademark is roughly $660, plus attorney fees, and the cost to purchase a VMC is $1,499 per year.
However, there is a free alternative solution for anyone who can't afford a VMC.
- Create a Google account with your company's email address.
- Change the profile picture to your company's logo.
- Wait up to 48 hours for the logo to become visible in the inbox.
Do not create the Google account using the "To manage my business" option. This account type isn't able to change its profile picture, and the account type can't be changed after its created.
For everyone else:
First, you will need complete the BIMI specification. Then, you will need to complete any additional requirements that each email service provider may have to display the logo in their inbox. This tutorial walks you through the process and explains everything you need to know.