BIMI (Brand Indicators for Message Identification) lets your verified brand logo appear next to authenticated messages in supporting mailbox providers — a visible trust signal and a small deterrent to impersonation. It is a DNS TXT record at default._bimi.yourdomain.com pointing to an SVG logo and, usually, a certificate.
BIMI has two prerequisites. First, DMARC must be at enforcement (p=quarantine or p=reject); a p=none policy does not qualify. Second, most major providers require a Verified Mark Certificate (VMC), which generally requires a registered trademark for the logo; some providers also accept a Common Mark Certificate (CMC) under narrower terms.
BIMI is a reward for doing email authentication properly, not a shortcut. See the guide on DMARC, SPF, DKIM and BIMI.