Do i need to invoice cutomers that i go to see and get paid on the day?

Im starting up my own business and i want to check out what i need to do in regards to invoicing.

I will be going to see the customers face to face and getting payment for the service we provide on the day. Does this mean i still need to invoice them whilst im there or do i just give them a detailed receipt?

An invoice or bill is a commercial document issued by a seller to the buyer, indicating the products, quantities, and agreed prices for products or services the seller has provided the buyer. An invoice indicates the buyer must pay the seller, according to the payment terms.

A receipt is a written acknowledgement that a specified article or sum of money has been received as an exchange

If the buyer pays on the day you can provide a detailed receipt

Depends on the product or service you are marketing.
Overhead and your suppliers billing cycles have a lot to
do with it. Positive cash flow and strong (interest free) credit
are essential. Typically, small businesses bill in 15-30 day post service cycles with a stipulation that late payment constitutes 9%-11% compounded interest. Of course, it is in print on both the contract (signed by both parties) and the invoice. Explain to your customer that maintaining a financially robust business is good for them because you'll be able to be around to serve them. Ask them if the competition is equally concerned with their needs. Great selling tool. Closes every time.

I'm pretty sure that invoices are only for payments on credit,
so if you arrange with the customer that they'll pay you at a future date you'd send them an invoice, if they pay in cash you should just send them a receipt.

A receipt should be fine and maybe a delivery note with the order if sending something out later on