I would like to know if there is a way to use the expression:

=iif([Order Sent]=yes,date(),null) can work by keep the date as the original date the order was sent, and not keep populating current date as days go by.

This expression is in a text box in a form. The Order Sent is a check box in that same form. They are both fields in the same table. The goal is to check the order sent box and auto populate what day it was sent, and when the product is received, to just uncheck the order sent box, and the date will go away.

Thanks in advance

In my opinion, it is difficult to understand what you really want to know. Do you mean that that expression is correctly working?