Locate the page you wish to edit. Click the edit tab, to launch the editor tool.
Move your mouse in the text where you wish to add an hr (horizontal line).
Click the Insert button on the toolbar. Then click Horizontal Line.
Once you have clicked the Horizontal Line button in the Insert menu, your line will have been added to the space you selected with your mouse.
Once you are done with other changes, click the three dots in the top right of the editor then hit Check Content and Submit.