Use a fax app that supports iPhone faxing (e.g., eFax, Fax.Plus, MyFax, or similar)
Open the fax app and sign in or create an account
Choose the option to send a fax
Select the document source (Files, Photos, or iCloud Drive) and add your document
If needed, convert the document to a fax-ready format using the app’s scan/convert feature
Enter the recipient fax number
Add a cover page if the app supports it
Review the fax preview and confirm page order
Send the fax
Keep the app open until the send status shows as successful
Save or download the confirmation/report from the app if available