Mail Merge

On a Mac you can do mailing labels, envelopes of lists from the Contacts app. No need to export to a word processor like with MS Office. Simply select a group within your contacts and do the Print command (command p). The dialog box with look like this if you use the "show details" button:

This seems to be totally undocumented but if you play with it a little, I think you may find it does what you want.

Sorry, I am not as familiar with iOS devices as I am with Mac computers. Consider asking the iPad side if this question in the iPAd forums here:

Using iPad

On the iMac, sure that feature has been around for years. On IOS, I don't know you should ask on an iPad forum for sure.

Just to add, the Contacts application has Help menu support on how to import CSV spreadsheet contacts into a new Contact group. You then select that specific group for the above label process.