Alt-D will take you to Detail tab, Alt-T to Totals tab, and Alt-H back to Header tab.

THANK YOU!!!! I've been Googling this for a week and hadn't found anything yet. You've just saved me soooo much time! 

You will find that almost all forms have shortcuts like this.  If the label name for a given control has an underlined character, this indicates that the control can be accessed via the keyboard directly by pressing the <ALT>  key and the underlined letter at the same time.  In a few rare instances, if there is more than one label using the same character, then pressing <ALT> and the underlined key again will take you to the second instance.  We try to avoid this which is why sometimes some might wonder why the first letter of the label was not used.

When dealing with tabs, any controls on the tab in focus will be used.  So if tab Header and tab Detail both contain a control with an underlined "Reason Code" character, it will go to the control on the tab in focus.

Hi CWI, if these suggested answer helped, please do mark either one as verified for the benefit of others in this forum . Thank you!

That's great. Thank you, my entries are already going quicker. 

That's great. Thank you, my entries are already going quicker. 

Review the Tutorials for a lot of other tips. There are also some settings you can customize in User Preferences related to how forms appear, defaults for some data and whether to substitute Enter key as Tab.

If you have Customizer, you can add & before a letter in a caption to represent a keyboard shortcut (verify they don't conflict with one another) and potentially abbreviate entry by moving controls (even to different frames or tabs). 

Also, for those with CZ, you can list controls by adding following code to a button or just invoke DP metadata:

Dim oFormDPMeta

Set oFormDPMeta = CreateObject("DPZMA001.cApplication")

If Not oFormDPMeta Is Nothing Then
oFormDPMeta.Activate(Form.moForm)
End If

Set oFormDPMeta = Nothing