There is a similarity between the configuration of QR & Barcode on Magento 1 and Magento 2 Backend. You are provided same features as the previous version of Magento.
To open Manage QR and Barcode page, you need to log in to your Magento 2 backend, then select Simicart and choose QR & Barcodes.
In Manage QR and Barcodes page, you can view a list that shows information of all codes in your site such as Barcode, QRcode, Product Sku, Created Date and Status.
Click on Add New Custom QR & Barcode button on the top right corner, you will be navigated to New Code page
On Manage QR & Barcodes page, click on the item you want do edit. You will be navigated to the Edit QR & Barcode page.