yes. what site or app are you using? nostr has things called keys. you have a public key which is your "username" and then you have a private key which is like your "password". you can never change the "username" or "password" and you must always keep the "password" safe because it unlocks the access to your "username"! so, keep your private key safe! 😉
Discussion
Btw I’m using damus on iOS.
Can I see your activity even if you are using a different client?
Yes you can. All of this apps or clients all work together because it's the same protocol. Kind of like email.
In Damus you'll see settings and keys. Your private key or secret key is what you need to backup and keep safe.
Feel free to keep asking questions. Goodnight for now.