Please could you help me to find out my password this computer, Ione dos S., where can i get that?

If the op is finding out the admin password the exact location is user library : click on finder > Go > hold option key > library > keychains > the password is stored in login.Keychain-db and the passwords are always encrypted the user cannot read them physically , even you restore the data from time machine the passwords cannot be read by the user ( just for security reason ) .

The login password is kept same as keychain access password an article Keychain for Mac: login keychain

It may be possible that the app that you are trying to update was purchased with another Apple ID. If that's the case, you will not be able to update it with your ID. If this is the case, you will need to delete the app from your Mac, and then, purchase it with your Apple ID.

The admin password is saved by the user and is written in safe place , and the serial of Mac can be found by clocking on apple logo > about this Mac .

And what is this - Ione dos S.

Please explain in easy language what is the issue you are facing in Mac .

If you forgot your Apple ID password - Apple Support

If you are referring to the admin password you created when you set up the Mac, try the suggestions in this article:

Change or reset the password of a macOS user account - Apple Support

And what is this - Ione dos S.

That appears to be the name of the user/account owner of the Mac.

Thanks ! Babowa