Directly in the insert interface, and then select φ in the formula. Below I will demonstrate the detailed operation steps:

(computer model: MacBook Air, software version: Word 202 1)

1. Open Word and click "Insert" above;

2. Click the formula above;

3. Click the right triangle twice;

4. Click φ above;

5.φ typing operation completed!

The above is a tutorial on how to type φ, I hope it will help you ~