I have a django webapp with multiple users logging in and fill in a form.
Some users may start filling in a form and lack some required data (e.g., a grant #) need
The issue is that you have multiple Forms.
Partial. Incomplete. Complete. Ready for this. Ready for that.
Indeed, you have a Form-per-stage of a workflow.
Nothing wrong with this at all.
Figure out where in the workflow you are.
Populate and present the form for the next stage.
Forms can inherit from each other to save repeating validation methods.