Microsoft Outlook 365 doesnt provide an easy way to export all of your Contacts to vCard files at once.
Fortunately, there is a little trick Ive learned that will accomplish this task.
Note: These steps are for the Outlook 365 desktop client.
Alternately you might email them to yourself if you wish to move them to another computer.
Neat trick, isnt it?
Maybe someday Microsoft will include an easier way to do this.