You can turn text, images, and shapes into links that perform any of several actions when you tap them during a presentation. Objects that have links appear just like normal objects in your presentation.
As you type text in a text box or shape, Keynote automatically detects valid web addresses (URLs) or email addresses. (The address must be followed by a space, tab, or return character, or one of many punctuation symbols, including quotation marks, parentheses, and brackets.) URLs and email addresses become active and are underlined to indicate that they’re links.
Tap 
, tap Presentation Tools, then tap Interactive Links.
Select the text or tap the object you want to link, then tap one of the following link destinations:
Slide: Links to another slide in the presentation. (Swipe the list to see all options.)
Webpage: Links to a webpage in a browser. Tap Link, then enter a link address.
Mail: Opens an email message with the address you specify. Tap To, then enter an email address.
Tap outside the Interactive Links tool to close it, then tap Done.
Tap , tap Presentation Tools, then tap Interactive Links.
Tap the blue arrow on an object, then make your changes.
To delete a link to a slide, tap None. To delete a webpage link or an email link, tap Webpage or Mail, then tap Remove Link.
Tap outside the Interactive Links tool to close it, then tap Done.