Yes, you can play PokerStars on mobile, but only via the dedicated iOS or Android app. It is not possible to play PokerStars on mobile without downloading the correct mobile poker app for your device. Is the PokerStars mobile app safe? The PokerStars mobile app is 100% safe.
Pay by mobile is a depositing method that directly bills your mobile bill instead of a bank account or debit card. Pay as you go customers will have deposits taken from available credit - while pay monthly customers will see the deposit amount on the following phone bill.