1. First, enter the pound sign (#) in MathType. Then, place the cursor on the pound sign, click the right mouse button, and select Mathematical Annotation from the pop-up menu.

2. In the pop-up dialog box, enter the words to be circled, such as "circle". Click OK, and a circle will be added above the pound sign, and the entered text will be displayed in the circle.

3. If you need to modify the text in the circle, you can click the pound sign again, then click the right mouse button, select Edit Mathematical Notes in the pop-up menu, and then modify the text in the dialog box.