A channel is the source of your shipments as they appear in Shiptheory. You can connect one or more channels to your Shiptheory account and set up different shipping rules to control how your orders are shipped depending on the channel the order was imported from.
Shiptheory supports many platforms including Brightpearl, Magento, Shopify, Amazon, eBay and Unleashed. You can read more about supported channels and request any we're missing here: Which Channels are supported by Shiptheory?