Health Flexible Spending Account contributions are from pre-tax money and are not included into taxable income - thus the amount reported in the box 1, 3, and 5 form W2 do not include HFSA contributions. The HFSA contribution may be reported in the box 14, but it will not affect your tax return.
You will not receive any other reporting form.
If you are deducting medical expenses on your tax return - you cannot include expenses you have already received reimbursement with tax-free dollars through your FSA.
Please find mor e information here - https://www.fsafeds.com/fsafeds/faq.asp
You are correct - your contribution to HFSA are not included into your taxable income on W2 and there is no need to report your contribution to the IRS on your income tax return.
Your distributions from HSFA are controlled by the administrator of your plan. The only your concern is that the same expense should not be deducted as medical expenses on your tax return and from HFSA.