In order to display the percentage field as a progress bar, please follow these steps:
In the Fields section of the form, click on a percent field.
Click to the Advanced section.
Turn on the Show as progress bar option.
The percent field is now be displaying as progress bar in the form.
Clicking on the progress bar will show the percentage value in a textbox. If you click outside the textbox, the progress bar will reappear, and if you pass the mouse over it, a tooltip with the percentage value will show up. This progress bar option is also available in Read only mode.