A quick thermal slip handles the vast majority of retail and food service transactions perfectly well — but some sales genuinely need more than a narrow strip of paper can provide, and it's worth knowing where that line sits.
A thermal receipt is built for speed and simplicity
Instant payment, walk-out transaction, straightforward itemized total — this is exactly what a thermal receipt is designed for, and it's the right choice for the vast majority of counter sales.
A full invoice is built for a more formal, documented transaction
B2B sales, larger purchases, anything requiring detailed company information for the buyer's own accounting, or transactions where payment happens later rather than instantly generally call for a proper invoice, not a thermal slip.
Company-to-company sales usually need an invoice
If the buyer is a business rather than an individual customer, they typically need a document with full company details on both sides for their own bookkeeping — a thermal receipt rarely has room or the right fields for this.
Large purchases benefit from the extra formality
Even for a walk-in customer, a large purchase (equipment, bulk order) often warrants a proper invoice alongside or instead of the thermal slip — it gives the buyer a more complete, better-organized record for warranty or accounting purposes.
Many businesses use both, for different transaction types
A retail counter might use thermal receipts for everyday walk-in sales and switch to full invoices for wholesale or business-to-business orders — there's no rule requiring one system for every sale type.