What is the best way to add lots of products for a shop? [closed]

So we have an application where marts are required to add their products on the app. There are lots of products in a mart so adding one by one manually would be really tough and boring. We were looking to use Barcode to add products, but most of the products the marts will have won't have barcodes. What would be the best, if not, the optimal way of making this product addition?