I have 2 boxes in box 15 but not letting me add the second box

[mlmshortygirl]

I need to add second line to Box 15. How do I do that

[DavidD66]

I assume you are entering your Form W-2 and have more than one state with income and possibly withholding.    After you enter the information for the first state, there should be a box just below that that says "Add another state".  Click on that, and add another state (second line).  

[VolvoGirl]

Box 15 on what?  W2 or 1099R?  Do you mean for 2 states or  for a State ID and State Employer #?   If you have 2 states listed there should be +Add a row.