Is there an online customer portal service with helpdesk, invoices and updates?

Question

Helpdesk

Hello colleagues!
Our company is engaged in the development and implementation of specialized software. Now the number of clients has increased, it's getting a little hard to send out updates and support clients by mail. Therefore, we are now looking for an online service that will allow us to solve our problems.
We have compiled the following list of requirements:
1. Ability to upload update files (we work on 1C).
2. The ability to start and track support requests
3. The ability to track and show the client the terms of contracts (subscription to software and technical support)
4. The ability to send notifications about software updates and software-related events
5. It is desirable to be able to give the client contracts and issue invoices through the system
6. Ability to customize, the ability to host on your domain (or your second level domain)
Thanks in advance for your answers!

Answer 1

You need a CRM with a support function (Helpdesk) or 2 separate systems and "friendship" between them.

Answer 2

https://flectrahq.com/ and free