Private key login is one of the two ways you can log in to the wallet and be allowed to operate virtual assets (the other is mnemonic login). It is formed by a random combination of random numbers and letters. When logging in, you must ensure that The private key string entered is correct.
When your wallet is logged in, you can find the "Backup mnemonic and private key" option on the "Wallet → Settings" page, where you can view the private key of the current wallet, please be sure to a safety backup of both (by writing on a piece of paper, or a secure device) to avoid any loss.
*Please do not send the private key to anyone, beware of the loss of digital assets.