We're currently in a migration process and before Hubspot we were using a service that offered an app integration plugin where customers could enter their questions which then have been available as tickets in that system.
I couldn't find any similar for Hubspot. Is there anything similar or do I need to create a plugin myself that makes use of Ticket API to create a ticket for any user questions that raised in our app?
You can allow customers to create tickets directly by using the Support Form functionality; you can find more info on this feature in the following Knowledge Base article: