Retirement tax questions

I'm trying to follow your suggestions and entering it as a 1099-R.  However it wants a code:  "Select a code that matches Box 7 on your 1099-R".  Since this form is not really labeled as a 1099-R, there is no Box 7 with a code.  This form I received has a box 7 for "Social Security Tips" (As mentioned before, it is a W-2...