Check your last December paystub which lists your total numbers for each tax year. However most employees can no longer deduct union dues on their federal tax return in tax years 2018 through 2025 as a result of the Tax Cuts and Jobs Act (TCJA) that Congress signed into law on December 22, 2017. 

Explanation of IRS Codes: box 12

 HSA info for taxes from IRS   Distributions From an HSA form 1099 SA

Are You Missing Out on These Educator Tax Deductions?

Educator Expenses     http://www.irs.gov/taxtopics/tc458.html
If you were an eligible educator, you can deduct up to $300 of qualified expenses you paid as an adjustment to gross income rather than as a miscellaneous itemized deduction. If you and your spouse are filing jointly and both of you were eligible educators, the maximum deduction is $600. However, neither spouse can deduct more than $300 of his or her qualified expenses. To qualify as an eligible educator you must be a kindergarten through grade 12 teacher, instructor, counselor, principal or aide for at least 900 hours a school year in a school that provides elementary or secondary education as determined under state law.

Form W-9

Form W-4

Form CT-W4