The solution!
Jobster has an internal 'Advanced Custom Fields' plugin so, to find the strings for '
Post or edit job' and '
Post or edit request' you need to go to one of those pages or from wp-admin, go to one of those pages and click edit page (default page editor), it will only show the page title but at the bottom of the page you will see "
Post/Edit Job Field" or "
Post/edit Request Field" and you will find the strings and field instructions that show up when you hover the fields on front-end, the strings are all there, .
Well, one week investigating and the solution was right on my face

And you can change the tabs layout for Post or Edit Job... And everything can be on the same page vertically instead of tabs.