Thunderbird: Send Contact to friend via mail

The common way is to export the contact to a .ldif or .vcf file as described here and simply send this file.

For a single contact you need to add it to a new address list first. This way it's possible to export individual contacts:

• right-click on your address book and choose “New List”
• choose a list name like “export” and add the contacts you want to send
  • alternatively you can use Ctrl + mouse drag to copy contacts from address books or other lists
• via “Extras”→“Export”, export the list in the desired format
• attach the file to your mail

It is not possible directly in Thunderbird.

But an extension exists that can do it: MoreFunctionsForAddressBook

• send directly a contact as vCard attachment (from 0.3.4 version)

See same question in Mozilla support forum