Q3. Are the wages I earn as an H-2A worker subject to U.S. federal income
tax?
A3. Yes. Wages you earn as an H-2A worker are subject to U.S. federal income
tax.
TIP: You should receive a Form W-2, Wage and Tax Statement, from your
employer for each year you work. You will need the W-2 to file with your U.S.
federal income tax return.
Q4. Are the wages I earn as an H-2A worker subject to U.S. Social Security
and Medicare taxes?
A4. No. Wages you earn as an H-2A worker are not subject to U.S. social security and Medicare taxes.
Q5. Am I required to file a U.S. federal income tax return?
A5. Yes. You are required to file a U.S. federal income tax return if you meet
the filing requirements as follows: Nonresident aliens should refer to the
Instructions for Form 1040NR, U.S. Nonresident Alien Income Tax Return or
Form 1040NR-EZ, U.S. Income Tax Return for Certain Non-resident Aliens
With No Dependents for information regarding filing requirements and special
conditions. Resident aliens should refer to the instructions for Form 1040, U.S.
Individual Income Tax Return, or Form 1040A, U.S. Individual Income Tax
Return, or Form 1040-EZ, Income Tax Return for Single and Joint Filers With
No Dependents, for more information regarding filing requirements and special
conditions.

https://www.irs.gov/pub/irs-pdf/p5144.pdf