Your question is somewhat confusing. Title indicating that you want know something about login Forms, but saying about Data Entry. I assume that you are in Edit mode on your form and when a Command Button is clicked the current Form must be changed into Data Entry Mode. If that is the case then write a one line Code as given below in the On Click Event procedure of the Command Button:
Me.DataEntry = True
You need another Command Button to come back to the Edit Mode with value setting False.