The RDO Transfer is only necessary if your TIN was originally registered in City A* and you wish to register in City B**.
*City A - City where your TIN is currently registered at.
**City B - City where you want to transfer / where you wish
to be transferred to.
For individuals who are just getting started with their BIR Registration, this is usually the FIRST step to be taken, before the actual registration process with the BIR.
This is because more often than not, they have already had a TIN when they started as employees, and once they have decided to get registered as self employed individuals, the business address they will register (which is, in most cases, their residential address) is not in the same RDO as their TIN's current address.
It is best to call your nearest RDO's hotline to ask and check where you TIN is currently registered at, just to be sure!