An invoice is a commercial document a seller issues to a buyer, laying out products, quantities, and agreed price. Most invoicing today happens electronically rather than on paper, but the underlying process hasn't changed: send the bill, wait for payment.
Where it still holds up, and where it doesn't
Invoicing is familiar — especially to older demographics — widely adopted, and cheaper to process than credit cards. The tradeoff is real bad-debt risk, and a market share that keeps shrinking as recurring billing gets more automated and functionality gets absorbed into mainstream software.
Where the market actually sits
There's no clear market leader in this space anymore. As automated recurring billing becomes the default, the need for standalone invoicing keeps declining — much of it has simply been absorbed into tools like QuickBooks.
Who should still support it
B2B merchants, and anyone serving government or nonprofit customers, should keep invoicing available — those buyers often require it. Cost varies by vendor but stays well under credit card processing rates. Payment aggregators and ACH are the natural alternatives.
Invoicing won't disappear entirely — for high-value or recurring transactions specifically, some merchants still prefer a check or wire transfer over eating credit card fees.