erplain has a very flexible sales workflow. You can start the sales process by creating any of the following documents:

  1. Estimate (or Quote)
  2. Sales Order
  3. Invoice

For more information about the Sales workflow, please refer to this article.

You can create an Invoice from an Estimate, a Sales Order, a Shipping Order or directly by going to the menu Sales > Invoices:

  • Then click on 'Create Invoice' and follow the instructions on the side of the form. It is recommended to start by selecting the customer as erplain will display automatically the default values (price level, location, currency,...) from this customer.

  • Next: add the products to the Invoice. You can find detailed instructions to add products in this article.

  • You can then add Notes for your customers, update the Terms & Conditions, add Internal notes for you and your team or attach files for later reference.

  • Save

PDF and email

  • Once you saved the Invoice, you can generate a PDF document by clicking on PDF.

  • You can then send it by email directly from erplain by clicking on 'Send by email':

You can change your PDF Settings from the Setting Menu > Company Settings > PDF Settings. More information in this article.

The status of the Invoice

The status of the Invoice can be "Unpaid", "Partially Paid", "Paid", "Cancelled" or "Draft". Once you create the Invoice, its status is "Unpaid". The status will be updated as you receive payments from your customer.

The Draft status can be enabled in the Settings > Company settings. If you select this option, your invoices will be created as Draft until you finalize them. Once finalized, they can't be edited or deleted.

To finalize an invoice, simply open the invoice and click on "Create final invoice":

Manage payments

When you receive a payment, go to the Invoice, click on 'Add payment', enter the amount paid, the method of payment and Notes (optional). Once all the payments add up to the total of the invoice, the status will automatically be updated to "Paid", otherwise, the status will be "Partially paid".

To add a Method of payment, simply start typing the text and press enter or click on the underlined text:


Creating an Invoice doesn't always change your inventory. If you created the Invoice from a Sales Order, then your On-Hand inventory is updated from the Shipping Orders, not from the Invoice.

Creating an Invoice directly without creating a Sales Order will decrease your On-Hand inventory. 

For more information about the Sales workflow and the inventory update, please refer to this article.

Product returns, Credit notes and Refunds

You can create Product returns directly from the Invoice and then create Credit Notes or Refunds from the Product returns. You can find more information about Returns, Credit notes and Refunds in this article.

Due dates

erplain calculates the invoice Due date based on the Terms of payment defined in the customer profile or based on your default Terms of payment (Company settings), if left blank in the customer profile.

If the invoice is created from a Sales order, the due date is calculated from the Shipping date of the Sales order.

If the invoice is created from a Shipping order, the due date is calculated from the Shipping date of the Shipping order.


If you need to take a deposit, then you should create a Sales Order first, then create an Invoice from the Sales Order. In the Invoice, simply update the quantities: 1 'Product A' instead of 15 for example. When comes the time to invoice the remaining amount, click on 'Create Invoice' from the Sales Order, it will show the remaining un-invoices quantities.

You can then create your Shipping Orders when you ship or deliver the products to your customer.


You can duplicate your Invoices should you need to make the same Invoice. Simply open any Invoice and click on 'Duplicate':

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