Create a field in jobs called “Status”. For these, I usually use “Available”, “Pending” or “Assigned”, “Complete” and “Cancelled”.
When the job is created, use the status available. Filter the list to available jobs.
When a user accepts a job, change the status to pending.
When a user completes the job, change it to complete.
You’ll want two user relation fields to jobs - poster and accepter. You’ll name these however applicable to your app. For a delivery app, we use User and Driver. For a healthcare app it might be Patient and Doctor.
When a user posts a job, add them to the poster field. Then they can see a history of all of the jobs they’ve posted
When a user accepts the job, add them to the accepter field. Then they can see all the jobs they’ve accepted.
I made a tutorial on this for a delivery app - https://youtu.be/2m6Rq2AQi4s
Hope this helps!