The native tokens of Binance Smart Chain (BSC) are BEP20.
To do most things on BSC, you will need to pay gas, which comes in the form of BEP20 BNB.
You will also need the BEP20 version of any token you want to trade, stake etc. on BSC.
You can go a few ways about converting your tokens to BEP20, but here are the ones we recommend: