My template:

1. What is this change supposed to do?

2. Why is this change needed?

3. How was it tested?

4. Is there anything else reviewers should know?

5. Link to issue:

There's no "What changed?" because that's the diff. Explain your intent, why you think it's a good idea, how you know you accomplished your intent, and any future work needed or other concerns noticed while making the change. PR descriptions suffer from the same problem as code comments by beginners: they often just describe the "what" when that's obvious from the code, when the "why" is what's needed. So try very hard to avoid doing that.