Product Catalog order & invoice for clients

Hi, I’m new here and trying to create a simple product catalog for a client, I’m looking at the template " Product Catalog" but I don’t know how to send an order form to the final client (where can I see how to create one), how the final client can chose the product, quantity, etc. I viewed most of the info and videos online but I didn’t find that yet…I already checked the product catalog page but still don’t know how to link the product catalog with an order form from the final client…
please help! thanks