I've lost the seed or recovery phrase for my wallet, what can I do?
Your seed phrase is the list of words, normally 15 or 24, that you are prompted to write down when you create a wallet using a wallet interface such as Eternl, Yoroi, Daedalus, Flint etc. This list of words should be stored very securely, preferably in more than one location, on paper or maybe even punched into a metal sheet and stored in a secret location. There are many products available that enable you to store your seed phrase in a way that it is safe even in the most extreme conditions. If you loose access to your wallet, maybe your phone or laptop breaks or is stolen, or maybe you have forgotten your spending password, restoring your wallet in a wallet interface using your seed phrase is the only way that you will be able to regain access to it.
If you have lost access to your seed phrase but still have access to your wallet then you should immediately create a new wallet, storing the seed phrase securely, then transfer all of your funds to your new secure wallet. If you have been staking your ada then please see the following link:
How do I move all of my ₳ to a new wallet and claim my 2 ₳ stake key deposit?
If you have lost your seed phrase and do not have access to your wallet there is no way to retrieve your funds.