In a page layout document: Tap in the corner of a page (so nothing is selected), then tap , tap Background, then do one of the following:
Use a color or gradient designed to go with the template: Tap Preset, swipe left or right to see all choices, then tap a color.
Use any color: Tap Color, then tap a color. You can also swipe left to the color wheel, then drag the slider around the wheel to choose a color. To preview colors on the page, touch and hold a color, then drag across the grid. Release your finger to select a color.
Use a two-color gradient fill: Tap Gradient, tap Start Color or End Color, then tap a color or swipe left to use the color wheel. To switch the gradient direction, tap Flip Color. To change the gradient angle, drag the Angle slider.
Fill with an image: Tap Image, tap Change Image, then choose or take a photo.
When you’re finished, tap anywhere on the page to dismiss the controls.
For more information about the fill options, see Add watermarks and background objects in Pages on iPad