I received my first-time H4 EAD card after my I-765 was approved, but my stand-alone H4 I-539 extension is still pending. Can I get my SSN and start working now, or do I need to wait for the I-539 approval?
You can use an approved, unexpired Employment Authorization Document (EAD) to prove to an employer that you are authorized to work and to obtain a Social Security Number (SSN). However, official rules state that USCIS will not make a decision on your Form I-765 until after they adjudicate your underlying Form I-539.
You can cross the SSN application off your list if you requested it on your Form I-765. You do not need to go in. The Social Security Administration mails the card to you after your EAD is approved.
You asked if you can get your SSN and start working now, or if you need to wait for the I-539 approval. Having an Employment Authorization Document (EAD) is one way to prove that you are authorized to work in the United States for a specific time period.
However, your situation involves a pending Form I-539. According to official USCIS rules, they will not make a decision on your Form I-765 until after they have adjudicated your Form I-539 and determined whether you are eligible for the underlying H-4 nonimmigrant status.
The approval of a Form I-765 does not grant you an immigration status. It simply provides authorization to work and serves as evidence of that authorization.
