Hi, I've never had an amount in the boxes for 12a-12d. In box 12a there's an amount of 6550DD so should i enter the letter code as DD and 6550 in the amount box?

[Critter]

Yes ... enter the code DD and the amount in the provided places.   This is the cost of your health insurance paid between your portion & what the employer paid.  This is an informational entry only, it doesn't effect your return.