Missouri has released a handbook providing instructions on how to prepare and file electronic W-2 records with the state. The document has changed in presentation, but the specifications for filing W-2s have not. Missouri follows the federal standard but has some minor changes for the RV state total record. The handbook also states that third-party filers now need to obtain an EFW2 submission account to file on behalf of others. Corrections to box 17 require paper W-2Cs and an amended MO-941 annual return. There is a new address for submitting paper W-2s to Missouri.
Source Sovos