Where should I add the Schema markup file that contains the NAP for magento based store?
Where should I add the Schema markup file that contains the NAP for magento based store? in the root directly or inside a specific file?
Also, where to add the products-shcema file and can it be in the same file?
Paul Thompson: Schema markup goes into the actual page. If using JSON-LD, as I assume from your question, it`s often inserted into the header template, but it can be anywhere before the closing </body> tag.
Typically the Business Schema (NAP) goes on every page, assuming you also have the address in text on each page as well.
Product Schema has to be specific to each product and is also inserted on each specific product page.