To create a receipt or invoice manually on the system go to Finance / Receipts or Invoices
Once there you'll see the list of all receipts or invoices (depending on the button you have selected on the menu) you have created and their status (paid, outstanding, cancelled)
To create a new one press and you'll see the next screen
when you press on the Item section you'll see this screen, where you can look for an article you have already created or just write one to use in this invoice only with the price and everything.
* As soon as you start writing you'll get a drop-down menu with all the articles created that match what you're writing, if you don't get any result then you don't have any article with those words or reference, or maybe any article at all, but doesn't matter cause you can type anything you like, and it will be saved on the receipt/invoice
* write the quantity and the price per unit and you'll see the program gets the total, if you could find the article on the previous step you just need to type in the quantity cause the price will be there already.
* If you want to include this invoice in any billing account press the magnifying glass or type the account
Once you finished filling in the fields press and it will be added to the receipt/invoice and you'll see at the bottom of the document that the totals were automatically added.
You can repeat the process of adding an article as many times as you need on the document and when you have all of them on the list and everything is filled simply press in or in depending on whether you want to charge the receipt/invoice right after or in the future.