Specs

invitation_email(
  user :: Haytni.user(),
  invitation :: Haytni.InvitablePlugin.invitation(),
  module :: module(),
  config :: Haytni.config()
) :: Bamboo.Email.t()

Email an invitation

In the invitation templates, user is the sender of the invitation, you have full access to it, so you can use any field from its schema so you can refer to it by its surname if you like.