Session hours vs packages
Bill by the session when the schedule varies, or sell a package of sessions in advance and draw it down. If you sell a package, show the sessions used, the sessions remaining and the expiry date. A package invoice that only shows a total invites a question about what is left.
Materials and test fees
Books, practice tests and platform fees can be passed through at cost or included in the rate. If you pass them through, keep the receipt and put the item on its own line. Do not add a materials charge that the parent did not agree to.
Cancellations and no-shows
A 24-hour cancellation policy is normal, and 50% of the session fee is a common charge. Put the rule in the invoice terms and apply it consistently. A no-show is not the same as a late cancellation; say which one you are billing.
Progress notes and records
A short note after each session — what was covered, what to practice — is good client service and good evidence if a payment is questioned. Keep the notes with the invoice and the session log.
Tax and terms
Tutoring is a service and may be exempt from sales tax in your state, but the rules vary. Private clients usually pay Net 7 or on receipt; schools and agencies may need a PO and Net 30.