Build reusable contract templates and send them to be signed for a gig.
Agreements are a Pro feature. You write a template once, then generate a copy of it for a specific gig with that gig's details filled in.
Keep separate templates for the situations you actually run into — a pub function and a wedding rarely want the same terms.
Signing links are per-agreement and work without logging in, so only send one to the person who should be signing it.