Hi @EmmanuelFlossie, Thank you for taking the time to reply, it helped clarify a lot of things. I will be using the suggested app, Thanks (: 

Hello, What is the most effective and accurate way to upload products to Merchant center, is it through the google app in Shopify store, If not, what other apps are best for this task(don't promote your app please, I need unbiased suggestions), When ...

Yes, this could work however, the products I sell require a gtin so if add an attribute and set to false Googlebot will disapprove my products

hello, my products are not being approved for listing in google, it says i need to add GTIN. well... i don't have it, any suggestions?