I already followed this https://help.shopify.com/en/api/reference documentation. But thing is i couldn't find the solution for how to write API class. Please can you send me sample code for upload a product to shopify store.?
Since you are using Laravel PHP Framework, I would suggest you to take a look at these docs on github: https://github.com/phpclassic/php-shopify
It is a simple SDK implementation of Shopify API in more object-oriented way.
I hope it helps :)