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Find your insurer's claims fax number, then fax the complete superbill with a cover page showing your name, member number, and page count. Keep the confirmation page and check the claim online or by phone, since insurers often take weeks to process a faxed claim and a missing page can stall it.
A superbill is the itemized receipt your provider gives you when they do not bill your insurance directly, most often for out-of-network care, therapy, or mental health visits. It is the document that turns a visit you already paid for into a claim. Faxing it is still a normal route, but it is also the route where small errors cost the most time, because a rejected claim can take a month to surface.
Every superbill carries the same core pieces. Provider details: name, practice address, phone number, tax ID, and National Provider Identifier (NPI) in the US. Patient details: your full name, date of birth, and member number. Visit details: date of service and place of service, such as office or telehealth. Then the two code sets that decide the claim: procedure codes (CPT codes) describing what was done, and diagnosis codes (ICD-10 codes) describing why. Finally, the amount you paid, and whether you are asking for reimbursement to yourself rather than payment to the provider.
Check the codes before you send anything. A superbill with a procedure code but no matching diagnosis code is one of the most common reasons a claim bounces. If anything looks blank or wrong, ask the provider's office to fix it first. Resending a corrected superbill is far faster than arguing about a denied claim later.
| Superbill field | Why the insurer needs it |
|---|---|
| Provider name, NPI, tax ID | Identifies who treated you and who gets paid |
| CPT procedure codes | Describe each service performed |
| ICD-10 diagnosis codes | Give the medical reason for each service |
| Date and place of service | Sets which plan year and coverage rules apply |
| Amount paid and proof of payment | Sets the reimbursement amount |
Use the claims fax number on the back of your insurance card, in the member portal, or in the claim instructions for out-of-network submissions. Do not use a general customer service fax line if a claims-specific line exists; general lines forward mail and faxes through extra hands, and each hand-off is a chance for pages to separate. Some insurers publish different fax numbers for medical claims, mental health claims, and pharmacy claims, so match the number to the kind of care on the superbill.
Before sending, confirm the deadline too. Many plans require claims within a set window after the date of service, often around a year but sometimes much shorter for certain benefits. A fax sent one day late is a denied claim, and the confirmation page will not save it.
Wait, then check. Insurers often take several weeks to show a faxed claim in the member portal, and the confirmation page only proves the fax went through, not that the claim was accepted. If nothing appears after the insurer's stated processing window, call with the fax date, the number you dialed, and the page count ready. That combination lets a representative trace the transmission instead of starting a fresh dispute.
If the claim is denied, the denial letter will name the reason, and a missing code or a missing page is fixable by resending a corrected superbill. Note the appeal or resubmission deadline on the denial letter itself; it is often shorter than the original filing window. In Canada, the equivalent process runs through private insurers and health spending accounts, which use similar itemized receipts and claim forms, though code sets and plan rules differ by insurer.
LetterAgent's fax service is currently available in testing for US and Canadian fax numbers. You describe the fax to your AI assistant, approve the exact quoted total, and pay once through Stripe. Fax is still in testing and activation is in progress, so do not rely on it for a claim sitting close to its filing deadline.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
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