It could take a couple of months for the FAA to send you the plastic Remote Pilot certification card.
In the meantime, you'll get a Temporary Certificate. You can fly Part 107 operations (for compensation) with a Temporary Certificate. You must have the Temporary Certificate in your possession when flying under Part 107.
How do you get a Temporary Certificate?
You'll need to fill out the application in IACRA after you pass your Remote Pilot test. Those steps are outlined here. This initiates the issuance of your certificates.
When do you get a Temporary Certificate?
The TSA needs to conduct a basic background check before issuing a Temporary Certificate.
Depending on the backlog, this could take anywhere from 3-10 days. You will be unable to fly under Part 107 during this time. I have heard from some students who waited as long as 2 weeks, unfortunately. This is rare, though.
The FAA will email you when the background check is complete and they have issued a Temporary Certificate. You'll print it out and keep it with you.
Even though the Certificate Number says "Pending," it is still a valid certificate. Your actual certificate number will be on the plastic card you receive in the mail. If you are applying for airspace authorization in LAANC, just put "Pending" where it asks for your certificate number.
Your Temporary Certificate is good for 120 days after the date of issue. If you haven't received your plastic card in the mail after two months, contact the FAA.