We begin with the fact that it is safer to keep your ADA in your own wallet instead of using an online service such as binance.com or kraken.com. This is because you maintain the custody of your investment at all times.
When you create your wallet, you will get a 15-24 word passphrase which you MUST maintain as safe as possible. In order to recover your wallet, you will be asked for this 15-24 word passphrase always maintaining the same order.
We strongly recommend that you write down these 15-24 words down on paper and never use online services e.g. email