Subcontractors: assignment, schedule and contract
In Lean, a subcontractor is a partner with the types of work they carry out. For each work order, you choose the subcontractor from those eligible for that work. Their assignment and cost sit on the project, so they count in job costing.
In their portal, the subcontractor sees their projects, their work orders in a calendar and a schedule, the documents and information for the assignment, their notifications and their item prices. They sign contracts digitally, and the signed document goes onto the file.
What they can see is defined in advance: only their own work, never your margins or internal notes.