In Illustrator, you can use the Ellipse tool to create circles. To do so, follow these steps:
1. Select the Ellipse tool from the Tools palette.
2. In the Options bar, select the Style drop-down menu and select the Round icon.
3. Drag the center of the circle to the desired location on the artboard.
4. Use the handles on the corners of the circle to resize it as needed.
5. To add text to the circle, select the Text tool from the Tools palette and position it over the center of the circle.
6. Type your text into the text box and then press Enter.
7. To finish, drag the fill handle ( located in the lower-right corner of the circle) to the colors of your choice.