What is customer id in post office passbook?

The customer ID is your main number at the post office. It is also called the CIF ID. CIF means Customer Information File.

It is one special number just for you. This number connects all of your accounts together in one place. So if you have a savings account and maybe another plan, the CIF ID links them. This helps the post office see all the accounts belong to you.

You can find this number on the first page of your passbook. It is usually printed near your name and account number. It is very important for things like using internet banking. The post office needs it to know who you are.