All methods are Boolean but the differences are:

1. isDisplayed(): method is used to verify whether any object on a site is present or not.
So, it’s applicable to any web object and returned true or false.

2. isEnabled(): used to confirm whether an element is Enable or disable.
If enable, it would return ‘true’ otherwise ‘false’.

3. isSelected(): method is only applicable for checkbox, drop-down, radio button on a site. it will also returned true or false.