You can however email the document to yourself as a PDF or Word doc and "open in" another app that does this very basic function.
Let me say that again VERY BASIC FUNCTION!
It is not possible to highlight text in pages except on ePub documents.
Let's hope Apple includes that option in their next update release.
If you would like to see this very basic function added to Pages for iOS in the future, let the good folks at Apple know of your needs:
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