As a fresh wholesaler, you can make it easier for your customers to order, simply on their mobile phone via WhatsApp. This way you can prepare a separate order list for each customer on which they can tick their products. Very easy for them: they walk to the pantry with their mobile phone and can easily choose, check and order their product.
The order arrives in your order system so that you can process it and prepare it for delivery. Payment is simply made via invoice afterwards.