Box 14 on W2 has description "After-Tax" with category as blank. What should I choose in the category. I have contributed after-tax 401k.
Box-14 of your W-2 is used by your employer to report amounts that don't go in any other boxes of your W-2. You can select other for the category.
Refer to the TurboTax article What is box 14 on my W-2 for?