They request the level1 verification. I assume this is for the basic info. Yet it is possible they would ask for further documentation depending on the nationality.. I don't know.
Most exchanges would make that a level2 verification so you would simply be able to fill in name, address, phone number, etc. to be able to complete level1.
I've never used OKX but this appears to be how it works at other exchanges and also at casinos.
You should complete the level1, otherwise they're going to find an excuse to seize your money for good.