Go go Configure>Extended Data. Select Work Order and select your field - also make note of the corresponding Cfield number. You may choose to change the display name in this step as well. ..
?
Change display type to Combo and then save.
Go to a Word Order screen in Met/Team and double-click on the field in the Extended Data tab (here they are only listed as C23 numbers so look for the C number you took note of or your new display name.) Click on the little gear icon (highlighted.)
?
That will take you to the combo data field.
Add your values (right click and add) and save: