Here's how to create a receipt, for something your client has already paid for, like a walk they paid for in cash. A receipt is an invoice that's saved as paid.
Create a receipt
Tap Invoices, then the + button. On iPad, the + is at the top of the invoice list.
Choose Receipt.
Choose the client and tap Next.
Check the pets and tap Next.
Choose how they paid, like Cash, and tap Next.
Tap + beside each service they paid for, or turn on Autopopulate to fill it from their appointments. Tap Next.
Check the date it covers and tap Next.
Tap Next on the due date and deposit screens. They don't matter for a receipt.
Check it and tap the ✓ to save. You'll find it under Paid.
What happens next
It's saved as paid today, with a payment for the full amount in the method you chose.
Walkies sends it to your client straight away as a receipt, saying how they paid. It isn't sent if New receipt notifications are turned off in Menu > Client notifications, or for that client.
Export it as a PDF from the ... menu. It's named as a receipt.
Good to know
Automatic surcharges aren't added to receipts. Add one yourself if you need to.
If the client hasn't paid yet, create an invoice instead. See How do I invoice a one-off charge?
If you've already sent an invoice and they've now paid it, don't create a receipt. Open the invoice and record the payment instead.