Ing to Boundy (2012), typically, a written contract will include: Date of agreement. Names of parties to the agreement. Preliminary clauses. Defined terms. Main contract clauses. Schedules/appendices and signature provisions (para. 5).
If your project has a well-defined scope of work, a lump sum contract is a straightforward solution since contractors should be able to accurately estimate costs. If the project scope is unclear, contractors can bid with time and materials contracts to mitigate risk.