If I understand correctly, you have a text box whose Control Source is set
to:
       =Date()
so that it always shows today's date.

If you wanted to record the date when a record was first entered:
1. Open your table in design view.
2. Add a new Date/Time field named (say) EnteredOn
3. In the lower pane of table design, set its Default Value property to:
       =Date()

If you want to record the date when the record was last changed:
1. In table design, add another Date/Time field named (say) UpdatedOn.
2. Open the form where you alter the data in design view.
3. Set the BeforeUpdate event of the *form* to:
       [Event Procedure]
4. Click the Build button beside the property.
   Access opens the code window.
5. Set up the code like this:
   Private Sub Form_BeforeUpdate(Cancel As Integer)
       Me.[UpdatedOn] = Date()
   End Sub

Note: If you want to record the time as well as the date, use =Now() instead
of =Date().