Bookkeeper invoicing tends to fall to the bottom of the list because client deadlines always come first. The practical fix is to make most fees collect on their own: a monthly bookkeeping fee on authorized autopay, a deposit before catch-up bookkeeping, and reminders for anything one-off.
Recurring billing for bookkeeping clients works best when the amount is predictable and the client agreed to it in writing. Put the fee in a signed engagement letter form and ask for a bank account on file. ACH payments for accounting firms usually cost less than cards on large recurring fees, so offer the bank option first.
Accounting firm payments also include the odd ones: a rush 1099 fee, an advisory call, a client who insists on Zelle. Send each as its own bill or flexible-amount link, record Zelle and Venmo payments when they arrive, and every client profile shows what is paid and what is open.
KadePay is not your general ledger and does not connect to your accounting software. It handles bookkeeping client onboarding, billing and collection, and you download transactions to record your firm's revenue wherever you keep your books.