1. First open the Word document to be edited, and click the Insert option to open it.

2. Then click "Answer Formula" in the pop-up window to select the required formula.

4. Then click the inverted triangle behind the open symbol in the pop-up window to expand the symbol options.

5. Then click Open Basic Mathematics and select "Handwriting".

6. Then choose the "X" in the handwriting.

7. That's it.