Set the featured image
The featured image is the image at the very top of the page, sometimes behind the page title. This image will also be used when sharing the page on social media.
Click the image to change it.
If a page does not have a featured image set, click Page Settings in the edit bar at the top right of the screen, then click Set featured image.
Show the title on top of the featured image
Click Page Settings in the edit bar at the top right of the screen, the click Page header style. In the first dropdown, choose either Text over image, or Text over image without overlay. Only use the latter when the image is dark enough for the text to be clearly readable.
Prevent image cropping
By default the featured image will be cropped to display at a fixed size. To show the whole image set the Image size dropdown to Full height via Page Settings > Page header, as above.
Remove the page header
To create a page without a page header (no featured image and no page title), set the Page header style to Hidden. Note that while in edit mode the page header will still display, to allow editing the page title. If the featured image is set, it will still be used for social media sharing, even if not displayed on the page itself.
Add page subtitle
Set the Show subtitle dropdown to Before title or After title via Page Settings > Page header, as above, then click the text to edit it.