Is Box 12a on my W2 for MY contributions or my employers contributions? I think they filled it in incorrectly.

[LindaA]

It may be for both contributions made by you and your employer:

• W-2 box 12 code W reports both your and your employer's contribution to your Health Savings Account (HSA). 
• W-2 box 12 code DD indicates the total cost of what you and your employer paid for your employer-sponsored health coverage plan.

Please see the FAQs below for more information about W-2 Box 12 codes.

What do all the letter codes in Box 12 of my W-2 mean?  https://ttlc.intuit.com/replies/3300234

How do I fill out the Box 12 information from my W-2? https://ttlc.intuit.com/replies/4785646