I got generated Registration Unique Code (RUC) but could not fill fee and city of examination centre for MBBS AIIMS 2019
The Final registration process for AIIMS MBBS is to be started from 21st february that is today. So you must wait till the day end.
Once the registration process will start, you will be able to pay the fee and choose the city of examination center.
Keep on visiting the official website for latest updates.