If a taxpayer does not have their required identification number by the return due date, what can they do?

When a taxpayer does not have their required identification number, the best course of action is to wait for the identification number before filing. This is because most tax returns require a valid identification number for processing. Filing without this number can lead to delays, complications, and potential penalties.

It's crucial to ensure that the return is accurate and complete when submitted, which includes all necessary identification information. By waiting for the identification number, the taxpayer can ensure that they are following the correct procedure and reducing the likelihood of errors that could affect their refund or tax obligations.

Choosing to file a regular return without the number or filing without it and risking a penalty may cause issues in the future, such as complicating the taxpayer's ability to claim credits or deductions. Thus, waiting for the identification number is the most prudent action in this scenario.