We’re looking to do something similar, and provide a menu for frequently requested tasks (employee onboarding/offboarding, computer setup/retirement, etc).
Unfortunately I don’t think a “service menu” workflow is natively supported in Zammad.
The Form channel can’t be customized for multiple kinds of requests.
Templates are designed to be used by the “dispatch” person answering the phone and creating tickets on behalf of the customer, rather than a customer submitting their own ticket.
Currently it seems like the best way to do this is to build a bunch of external web forms in your intranet, that then create a ticket using Zammad API.
If the “build your own solution” API method isn’t feasible, an alternative method would be to use something like Microsoft Forms to send emails to Zammad, and use Triggers to assign tags and groups.