A Code W in Box 12 of your W-2 Form indicates that you had employer contributions (including employee contributions through a cafeteria plan) to your employee health savings account (HSA). It also means that you have a high deductible health insurance plan.
A high deductible health plan (HDHP) is health insurance with a lower premium and higher deductible than a traditional health plan. Having an HDHP is one of the requirements for a health savings account (HSA).
Yes. You are required to enter the code and dollar amount listed in box 12 on your tax return as you may owe tax if you used funds from the account for non-medical purposes. You may also owe a penalty if you contributed more than the maximum allowed amount for 2017.
Since your new to reporting an HSA account, it may help to get familiar with thetax forms you may not be familiar with: