Only if you bought something today.

Generally the Session Date is whatever you think today is.  When the program is opened, you set the Session Date to today.  I hit the down arrow on the Session Date dialog and it always brings the date to today as long as today is in the same fiscal year.

When you are doing data entry, the Session Date is used to help the user with date-related messages so you don't mistakenly hit a 3 instead of a 6 for the month and post into an incorrect period.  You will receive the message about posting to and altering reporting on a previous period.

The date of an invoice is the date of an invoice.  So if you are doing bookkeeping today, have an invoice that has not been entered and it is dated Jun 30 you would still have a session date of Jul 27 but post the entry to Jun 30.

I am giving a general perspective on how it is used.  As a consultant who sometimes has to catch up on books, I will sometimes keep the session date on Jan 31 to post entries for January so that if I receive a date-related message I know I have typed something incorrectly in the wrong month.  I am doing this now with a set of books working on 2019.  My session date is currently Apr 30 because I am working on April credit card statements and bank recs.

Thank you greatly!!! This is a great response.