You can use the UCase function to convert to all upper case. When do you
want to do this? In the displayed value in the form's textbox? In the
table's field?
For example, you can do this in the display using the control's AfterUpdate
event. Use code similar to this in that event:
Private Sub ControlName_AfterUpdate()
Me.ControlName.Value = UCase(Me.ControlName.Value)
End Sub
Replace generic name of control with real name.