In the app. Open More, tap your name at the top to open Settings, then Security › Request account deletion. It writes the email for you with your account and salon filled in.
By email. Write to support@saloonerp.com from the address you sign in with, with the subject “Account deletion request”. Tell us your salon's name, and whether you want only your own login removed or, if you own the salon, the whole workspace closed.
Nothing is deleted the moment you ask. We reply to confirm it is really you, and that you want it done.