Office 365 (Outlook 2013 / 2016 / 2019 for Win) - How to Export / Import Contacts
When you export your contacts from Outlook, a copy of your contacts is saved to a CSV file, or other file type. You can then use this file to import your contacts to another email account.
For the most current information on exporting and importing contacts from Outlook, please see the following Microsoft support article: https://support.office.com/en-us/article/export-contacts-from-outlook-10f09abd-643c-4495-bb80-543714eca73f.