POS transactions are generally quick, hence should have as less dependency as possible. In ERPNext, you can create POS Invoices even when not connected to the internet.
POS Invoices created in the offline mode will be saved locally in the browser. If internet connection is lost which creating POS Invoice, you will still be able can proceed forward. Once internet connection is available again, offline invoices will be synced, and pushed onto your ERPNext account. To learn more on how POS Invoices can be created when offline, [check here.](https://frappe.io/blog/blog/erpnext-features/offline-pos-in-erpnext-7)
In ERPNext all Sales and Purchase transactions, like Sales Invoice, Quotation, Sales Order, Purchase Order etc. can be edited via the POS. There two steps to Setup POS:
* Update Stock: If this is checked, Stock Ledger Entries will be made when you “Submit” this Sales Invoice thereby eliminating the need for a separate Delivery Note.
* In your Items table, update inventory information like Warehouse (saved as default), Serial Number, or Batch Number if applicable.
* Update Payment Details like your Bank / Cash Account, Paid amount etc.
* If you are writing off certain amount. For example when you receive extra cash as a result of not having exact denomination of change, check on ‘Write off Outstanding Amount’ and set the Account.
You can select one of the existing Customer from the Customer master. If Customer doesn't exist in the Customer master, enter Customer Name in the POS Invoice view itself. On creation of POS Invoice, Customer will be auto-created in the Customer master.
At the billing counter, the retailer needs to select Items which the consumer buys. In the POS interface you can select an Item by two methods. One, is by clicking on the Item image and the other, is through the Barcode / Serial No.
**Select Item** \- To select a product click on the Item image and add it into the cart. A cart is an area that prepares a customer for checkout by allowing to edit product information, adjust taxes and add discounts.
**Barcode / Serial No** \- A Barcode / Serial No is an optical machine-readable representation of data relating to the object to which it is attached. Enter Barcode / Serial No in the box as shown in the image below and pause for a second, the item will be automatically added to the cart.