In order to add a new quantity of product:
Go to the "Products".
Choose the product for which you want to add the quantity.
Click on (...) dots and "Edit", as shown below:
4. You will receive a pop-up to update the product.
5. Add the "In Stock Quantity", by clicking on (+) icon.
6. When you click on the add icon, you will see another pop-up for increasing stock.
7. Add the desired product quantity and click "Save".
