When you create a new Hedera Account on Xact Wallet, some precious informations are provided. And you have to save it on your end, securely. Remember that Xact Wallet nor Hedera will be able to provide you these informations again.
Your account ID: it's your account address on Hedera. You will need it to receive tokens and HBAR for example.
Your private key: it's your key to access your account. Never share it to anyone. And be sure to secure it on your end.
Your mnemonic phrase: it's your private seed phrase, needed to recover your account if you lost your private key. Never share it to anyone, write it down and save it on your end securely.