If you are applying for a PF transfer request online at the UAN member portal then you will see an option called enter MID/UAN. The full form of MID is Member ID, which means your PF account number. When you are transferring your PF amount from your previous company to a new company then you need to enter either previous PF account number or previous UAN number ( if you have any).
So MID means Member ID, simply PF account number. It looks like GRVSP007801200012345. After entering your member ID all your previous PF details will be visible to you on the screen. If all those details match with your present PF account then you can transfer your PF amount without any problem.
Also read: How to get MID for PF Transfer Online
How to Get MID If I Forgot
If you are using the same UAN for all your PF accounts then you can easily find your PF member ID by going to service history option in the UAN member portal.
If you have multiple UAN numbers then you need to log in with that UAN in UAN portal to find your EPF member id.
If you forgot your UAN, then you need to find it by using know your UAN option in UAN member portal, for this your mobile number must be registered with your PF account, otherwise it is not possible to find your UAN online.
What is the format of MID (Member ID)
Member ID is also known as PF account number, it consists of office code, regional code, establishment code, establishment extension, and last 7 digits are unique PF account numbers of the employees working in the same company.
MIB or UAN which is best for PF transfer request
If your PF accounts are linked to the same UAN then you need to enter your PF MID to transfer your PF amount from old company to new company.
If you have multiple UANs then you need to enter your old UAN to transfer your PF amount.