The first thing that matters to them is your privacy. Once you have created and completed your resume profile, you can set it to "Inactive" with the toggle button. This makes sure that no one else can see it, apart from you. To apply for jobs, you will have to mark your resume profile as "active", with the toggle button, and then you can apply for multiple jobs, and then you can mark as inactive again after you have finished applying. You can also contact Upwork Customer Service for further information.