I worked for a staffing agency based out of Texas but in MO. They marked MO in box 15 but nothing in the state code. What should i do?

[ThomasM125]

You may need the state code to e-file your tax return but sometimes it will go through without it. It is not necessary to prepare your return otherwise. If you find you can't e-file it without the code, you can contact the department of revenue to see if they will give it to you. 

Here is their website:

MO department of revenue