Customer Service solution for dev shop

Hello Redditors,
I'm looking for recommendations for a customer service solution.

We develop and maintain custom software (mainly web applications) and we would like to standardize our customer service processes. So I'm looking for a user friendly cloud-based solution that is suitable for handling client requests, including:

– bug reports
– "how do I do this" type of questions (it's a big plus if it has some sort of client wiki)
– small change requests (e.g. "change the color of the button")
– bigger change requests (e.g. "modify the order of this workflow")
– new feature requests

The last two types of request usually needs several back-and-forths, attaching documents, pictures etc. Sometimes a call with the client is necessary. Sometimes an estimate is necessary.

We use Azure Devops for development, but it's not particularly handy as a client-facing tool.

Any recommendation would be appreciated!