This article will show you how to manage Shopify sales channels in the PIM.
...
First, you need to import the sales channels you have in Shopify. Go to Configuration > Channels and select your Shopify channel. Go to the Import tab and click on the Import Shopify Sales Channels button to start the import. The process will run in background. (You can check the progress in the Jobs section).
...
Once the sales channels are imported, go back to the Details tab and select the sales channels you want to enable.
...
When the PIM will create creates a new product to Shopify it will enable the selected sales channels.