To Edit Folder follow these steps:
Tap on the menu icon located at top left corner.
A screen will slide from left side.
Tap on Folder icon, all folders will be shown.
If you are using mouse, right click on folder to edit.
If you are using touch device, long press on a folder to edit.
A pop-up menu will be shown.
Tap on Edit menu.
Folder will be opened in edit mode.
Make changes and tap on save button.