How to double space in Pages for iPad?

Highlight the desired text, click on the format tool/paintbrush and go to layout and choose line spacing.

Double spacing is double spacing whether you are using Pages or Word. Double spacing is dependent upon the font size that you are using in the document no matter which word processing app that you use.

Pages on the iPad has limited fonts and chances are pretty good that if you import a Word file into Pages on the iPad, there will be some formatting or font issues.

But once again, Helvetica in Pages is pretty much the same Helvetica as you would be using in Word. If you use a font in Word that is not available in Pages, you will see a warning message that some elements of the original document have been changed.