try for both.
while creating a Blog dont forgot to use both in the same website.
But if you are a beginner then start from amazon.
Amazon will help you in promotions and every thing you require for promotion is readily available with amazon. there is a community section in amazon. go there and ask questions and get answers as well.
Go to this homepage if you want to know how to be a well-performing student without any time waste!
Amazon is better than Shopify. It is one of the best platform to make money online and earn a passive income.
Always amazon is the best option to explore. However all the terms and conditions might have got changed due to COVID'19. We should go through these before taking any decision.