The important facts for the IRS are,
1. The expense was for qualifying medical care. That means, you need a statement that shows what the expense was. Expenses for cosmetic procedures are usually not allowed except under specific circumstances. Expenses for drugs or treatments that are not approved in the US are not allowed, even if you travel overseas where the drug or procedure is legal. There are other rules as well.
2. The expense was for yourself, your spouse, or your dependents. That means you need proof of whom the procedure was performed on. A procedure performed on your wife before your marriage would not be eligible.
3. You don't claim reimbursement for expenses that were also covered by insurance. So you need your EOB. Your EOB may also satisfy #1 and #2, it depends.
4. The expenses were incurred (the procedure was performed) after the date you opened your HSA.
3.
