Hover over the name of the page you want to move to reveal the page menu. Select the menu icon then Move.
In the Move dialog box select where you want to move the page by selecting:
Destination Space
Target Page
Position
The preview lets you check where the page will go to help you get the correct location.
When adding as a child page, it will appear at the bottom of all existing child pages, so you may have to scroll through the preview to find its location.
(Optional) Select the Rename pages check box to update the name of the page after you move it.
You are required to change the name if there is a page with the same name in the target space.
You can add text before or after the existing name using the Add Prefix and Add Suffix fields. The preview lets you check the output before you save.
Select Apply to move the page.