Add a downloadable product to a cart [Web API Tutorial]

To add a downloadable product to a cart, you must provide SKU, ..., and the quote ID, which was generated when the cart was created. But first, you need to have the product in the inventory. If you already have one then copy and modify payload to fulfil the requirements otherwise we assume that you followed these instructions to Create a downloadable product with REST API on MSI. The following example adds a Downloadable Product MSM 1 to the cart.