Private key is not something you can easily lay your hands on. Also it depends on the kind of wallets you are making use of, if it is exchange wallet you can't possibly have access to the private key. However if you are making use of non custodial wallets then it is possible for you to have access to your private keys, you can even export your private key from the wallet. Therefore , it totally depends on the process we undertake while creating our wallet. If the wallet was actually created by you and during the process you saved your seed phrase then you already have access to your private keys however if you are making use of exchange the possibility of having access to your private key is not there.