They have clearly mentioned this in their help page.
Freelancers that are required to verify but do not do so within 7 days of our notification will have their accounts placed on hold. The hold will prevent freelancers from withdrawing earnings, submitting proposals to new jobs, accepting direct hires, or showing up in search results. Any active proposals that have been submitted will also be canceled. The hold will not affect your ability to work on existing contracts.
Once you successfully pass the verification process, this hold will be removed.