iSeller provides the feature to convert Standard product types to Composite product types. Please follow these steps.
Step 1: Please select one of the products that has Standard type and will be changed to Composite type.
Step 2: Then, click the icon in the top right corner as shown in the below picture.
Step 3: Select "Convert to composite product".
Step 4: Then you will automatically be directed to Inventory panel and an Include Products column will appear, where in that column you can fill in the products which included in the composite products.
To find out more information about composite products, how to add and change composite products, please read the Composite Product Settings article.