Can I find my bitcoin private key?
Your question is either incomplete or you don’t understand what private key means.
You need to have a wallet before you can get a private key or seed phrase. You need to know the difference between custodial and non custodial wallets, and you also need to know the difference between open source and closed source wallets.
Learnmeabitcoin.com is a book you should make reference to, you will understand better there.
Although the OP seems to ask an incomplete question which many of us do not know where the question is directed at. But the website,
Learnmeabitcoin.com is a very good place for beginners to start from, it teaches both the basis you need to know about bitcoin and also went deep into the technical aspect of bitcoin.
At OP, you can’t get a private key if you don’t have a wallet. You need to create a non-custodial wallet before you can have access to a private key that can be used for your wallet to sign transactions. If you don’t have any, you can create one and if you’ve lost it, having access to your seed phrase can make you regenerate another one.