You can do this either way.. BUT if you’re using the same data for both stores, it may be more convenient to put them both on the same business. That way, you would just have to add another Shopify store to your current business. Follow these quick steps to do so:
Step 1: Go to your Channels screen. You will see your current Shopify app:
Step 2: Under “Available”, select either Shopify or Amazon, depending on your marketplace:
Step 3: After clicking on either Amazon or Shopify, this screen will pop up. Select “Activate”:
Step 4: After clicking “Activate”, it will ask you to enter your store URL:
Click “Install” and you will then have to Shopify accounts under the same business!