If you have a Mostbet promo code, you can use it during registration. It is also important to read and agree to the Betting Transaction and Acceptance Rules on the Betting Agent's website. After that, don't forget to activate your account with an sms code or email.
Remember that after that you have to enter the information in your personal profile. The bookmaker operates under license, so after registering with Mostbet you need to confirm your identity and age. This is how the bookmaker's office fights cheaters and attempts at foul play.