How can I collect anonymous employee feedback in Microsoft Teams?

Using forms is kind of the "Techy" solution to a very people-intensive process. There are plenty of different ways you can get: "Answers to questions anonymously"

That's not the point of anonymous surveys/feedback. They need to be carefully constructed based on the context. 

For example:

• Is the anonymous feedback going to be about an individual? 
• Are direct reports giving anonymous feedback to their manager, or about their manager?
• Is it a survey about a new company policy?

You need different survey and feedback templates for each of these situations that will both quantitative data, through question types like: multiple choice, likert scale, rating, ranking, etc.

As well as qualitative responses through open-ended questions. 

You would also need to automate there is less admin work, and feed that data to Power BI so you can analyze results easily.

Sorry if this was a very long-winded answer but I really think context matters here. There are plenty of great third party apps you can use for this. The one we use is Teamflect because it really doesn't feel third party. Fits our Teams environment perfectly.

Let me know if this helped. I know this is a tech forum but let's try to keep in mind the tech is sometimes there to assist people processes primarily