The acknowledgement number in an Income Tax Return (ITR) is a unique number that is generated when the ITR is filed and submitted to the Income Tax Department. It is a confirmation that the Income Tax Return has been received by the department and provides a tracking number that can be used to track the status of the return. The acknowledgement number is provided in the ITR-V form, which is a one-page document that is received when an ITR is filed online without using a digital signature. The ITR-V form is delivered in a password-protected zip file to the assessee’s email address to ensure that only the intended user may access it. The ITR-V password is made up of the assessee’s PAN number (in tiny letters) and their birthdate. To download a copy of the acknowledgement, the assessee must also have access to their user ID, which is also known as their PAN, and the login password. The acknowledgement number can also be found on the ITR-V received on the registered email after e-filing the return.