Wix offers a range of slots across Wix app pages, for which you can build plugins.
When developing a plugin, you need to explicitly declare the specific slots in which users are able to place it. If you set your plugin to be automatically placed in a slot on installation, it will be placed in the first available slot according to the order you defined. If that slot is occupied, it will be placed in the next available slot, and so on. If there are no available slots, it will not be placed.
To enable plugins to communicate with their hosts, each slot supports an API that provides data about the plugin's context (for example the productId of the current product on the Product page). Use this API when you code your plugin's logic in Wix Blocks.
For details about the slots available on each app page, as well as the API they support, see: