vCard
A standard contact-card file (.vcf) that adds someone to an address book.
A vCard is a small text file holding a name, title, company, phone numbers, emails and addresses. Phones and email apps import it in one tap.
Some signatures link to a hosted vCard so recipients can save the sender’s details. Attaching a .vcf to every email is less popular: it clutters threads and can look like an unexpected attachment.