If you want your customers to pay for goods before receiving them, you can send a pro forma invoice to them. Pro forma invoice will show exactly what and how they will be charged. Also, your customers will be sure your quotation will not be changed.
With the Pro Forma invoice feature, you can send invoices to your customers and get paid through your own Shopify store. When you send a pro forma invoice to your customer, they will receive an email about it. When they click on the link they will be redirected to your store’s checkout page. They will just enter their details to make a payment. After the payment, a regular order will be placed on your Shopify store. After that, your store can continue functioning as before
Easy Invoice+ is the only invoicing solution which lets you get paid through your own Shopify store. Rest of the invoicing solutions needs to be configured with an external payment gateway and they work independently from your Shopify store.