It is currently not possible to delete a job as this would possibly affect the thread of communications, activities (visits, routes, etc.) and documents (quotes, invoices, etc.) related to it.
If your goal is to streamline the search from the job list, we suggest the following:
Step 1: Close all jobs that are not relevant and/or have been completed.
Click on the display tab at the right of your screen in the "jobs list" tab
Check the "Status" box to add it to you columns view (if it is not already there)
Select the jobs to close by clicking in the boxes
Click on "Status" in the header, select the status "Closed", then click on "Update Status".
Step 2: Sort the "Status" column to facilitate your searches
Go to the top of the "Status" column and click on the arrows to sort.
This will ensure that the "closed" jobs will be grouped at the bottom of the list to lighten your view and make it easier to manage.