Self-custody is a method to store crypto assets independently in a wallet that is not kept or controlled by a third party. This is like keeping paper money in your wallet, not in the bank. The purpose and function of the method are to ensure that you take full control of your assets. The concept itself is in line with the principle of decentralization which no longer utilizes third-party companies.
You can choose between several non-custodial wallets such as a digital or a physical wallet. Access to non-custodial wallets utilizes private keys. Private keys are a string of words that are the only access to the assets in your wallet.
The method has become the choice for many crypto investors because it is safer. You can read more about self-custody in the article “Understanding Self-Custody: How to Store Your Crypto Safely“.