Freshdesk lets you support multiple products by creating dedicated portals for each product. Any ticket created from these multiple product portals would come into one central helpdesk and agents could work on these tickets from a single location. If your organisation has various products, this would be the best option for you.
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Under Admin > Channels > Portals > Edit(corresponding to the portal name), you would have the option to provide the Portal URL. Here, you could provide a vanity URL like help.yourcompany.com (help is the subdomain) and associate it with your Product portal.
Before using this field please ensure that you have created a CNAME record in your DNS Zone file to point help.yourcompany.com to yourcompany.freshdesk.com(your Freshdesk Account URL). Once this is done, you would be able to access the newly created Product Portal using the specified Portal URL.
For each portal on your account, you would have one dedicated primary email address associated with it. The main portal will have a similar primary support email and the product portal will have it's own distinct primary email address.
Existing emails cannot be used while creating a new product. You would have to add a new/unique email address and associated it with the New Product which is being created.
While creating multiple products, you could set a distinct branding for tickets created through emails. You could have this done by setting up a dedicated support email addresses for each Product.
When you create a new product(under Admin > Support Operations > Multiple Products > New Product), you would be asked to provide a separate support email address for that portal. This would be the primary support email address for that product portal and emails sent to this email would get created as tickets and would be updated with the corresponding Product. By default, replies to customers would also be sent through this dedicated email address.
You would be able to set-up feedback widgets that are dedicated to specific product portal. You will be able to have this done by making modifications to the widget code that you add. The product URL would have to be changed in the respective product in the "src" field of the widget code.
You could configure the Solution Articles such that each product has a different KBase. This could be set up under Admin > Channels > Portals > Select the Product Portal-->Under Portal Categories, select the respective Solution Category to be displayed for that product portal.
Yes, you can allocate a unique group for each product in the portal. While creating a portal under Admin> Support Operations > Multiple products, there is an option to choose an email address and a group for that particular product as shown in the image below :