Add a border to an object in Keynote on iPad
You can add a border, such as a picture frame or a dotted line, around an image, shape, text box, or video, then modify the border’s thickness, color, and other attributes.
Note: To add or change a border for a chart, see Add a border to a chart.
Tap to select an image, shape, text box, or video, or select multiple objects.
Tap , tap Style, then tap to turn on Border.
Use the controls that appear to adjust the look of the border.