Using rest api to build custom e-commerce

I am trying to build my own e-commerce website… but I have couple quest.
1- I didn’t know how to use these APIs (
for example how to pass item_code ??
erpnext.shopping_cart.product.get_product_info (item_code)
2- where can I get API methods of (signUp , Updating my stock when user submit order)?

Hi @kyabroudi

Please check

documentation of Rest API

Make sales invoice using rest api with enabled update stock option