A Secret Recovery Phrase (also known as a seed phrase or mnemonic) is a series of words generated by your cryptocurrency wallet that give you access to the crypto associated with that wallet. Think of a wallet as being similar to a password manager for crypto, and the seed phrase as being like the master password. As long as you have your seed phrase, you’ll have access to all of the crypto associated with the wallet that generated the phrase — even if you delete or lose the wallet.
DO NOT share your Secret Recovery Phrase with anyone! If someone has access to your secret phrase, they will have access to your wallet. Phantom support will NEVER ask you for your secret phrase or your private key.