Does anyone have a tutotrial on how to upgrade the version in Debian? If I install it from the apt then the service remained connected to the 9.6 and not the 10

Does anyone have a tutotrial on how to upgrade the version in Debian? If I install it from the apt then the service remained connected to the 9.6 and not the 10. Plus, I've to migrate all the configs, is there anaything that helps in doing this?