Amj190

Hello, I am a student studying PHP and have been asked to create a website that has the ability to a user to update their username, password and email. At the moment, a user can sign up, and they give their username, password and email, which is then stored on a server. I don't dislike PHP at all, but my teacher did not teach us anything - he gave us links to pages, and we have all had to learn it ourselves as a result (not terrible but at least giving some help would have been appreciated). I am unsure how to do this, as he gave us no links or help on how to do this, I have tried looking up solutions online but its a little overwhelming some of the stuff I have found - if somebody can explain to me how I can allow a user to update these things, I would very much appreciate it. Thank you.