You can quickly edit or add a Location for a job from the Jobs list, by clicking on the Billing or Contact name to open the Contact drawer for the intended job > Locations tab.

In the Locations tab, you can edit a Location that's already exists, (you can also add a new one by clicking on the + symbol).

Once done, Save the details and click off the drawer to close it.

You can also edit the Location by clicking on the Edit pen for the Job to open the modal, and selecting Locations in the Client information section.