You can embed the Raspberry Pi in any end-product you want.
For mass production, the Compute ModuleCompute Module may be a better choice. The Compute Module is a Raspberry Pi in a more flexible form factor, intended for industrial application.
You cannot use the words Raspberry Pi to promote your product without permission. Raspberry Pi is trademarked.
You will have to ensure you follow the terms of the software licences for any software you embed in your product.