How do I use BTC to pay for something?

I have a renewal that only will take BTC/SATS.

It gives me a QR code. which CDC doesnt recognize. and a wallet address. I know CDC doesnt sell SATS. but I do have some BTC I can send. But how?

I dont see where I can send fractional BTC to a wallet address.

I opened 2 other exchanges and noticed the USD to SATS is crazy??

The renewal is about 127k SATS. and claims its about $95.00usd.

But on OKX exchange. $95usd is over 6billion SATS????

Please advise. I am totally lost.