Does the customer portal section (in commerce) have the option for us to add additional documents?

Say a customer purchases an item and we want them to always have access to the instructions / owners manual / warranty information. Or if we need to use Zoho Sign for documents...

How might one have that kind of info show up in the customer portal?

Is there perhaps an easy way to assign a digital document with a tangible product so that they are always linked?

Additionally, we utilize other zoho apps, such as showtime.... is there a way for us to have their training info within the portal as well? Would I have to sell training done via Zoho Showtime through Zoho Commerce?