Insert a circle chart in the same manners as you would insert any other empower chart. What makes a circle chart different is that its user is unable to use chart features such as Lines; also, other settings such as Data Labels are not possible.
Click on Data Labels in the Action Bar in order to activate data labels of the chart. In Value label you can activate the value of the circle chart by toggling the Show Value slider. You can also set the number format as well as display the percentage of the value. You also have the possibility to set the decimal place of your percentage. Finally, you have the option to display the category names by activating Show Category Name.
In order to improve legibility of data labels of a background using the same color, you can insert transparent backgrounds for labels by activating Show data label background. In addition, you can reset the data labels to their original formatting by clicking Reset Data Labels.