There are pad designs on the PCB, but they are covered by solder mask ink. What should I do?

If you find that some solder pads are covered by green oil, you can handle it like this:

If these solder pads do not need to be soldered, you can leave them as they are, as it will not affect the usage. If these solder pads need to be soldered or tested, you need to modify the Gerber files and re-produce the PCB to ensure that the solder pads are exposed.

Before production, you can check the solder mask file (GTS/GTL) to confirm whether the window position is correct. Of course, PCBfast will also perform the check for you.