Apple Mail (or Mac Mail) addresses can be exported from your address book, from your iCloud account, following the same steps as for iOS. However, your Apple Mail contacts may not be in your Address Book or Contacts app. To save your Mac Mail remembered addresses to the Contacts app:
- Open the Mail application on your Mac.
- Select Window from the top menu bar and click on Previous Recipients.
- Select all contacts. One way to do this is to click the top most contact, then while holding down the shift key, scroll down to the bottom-most contact and click that.
- Click on Add to Contacts.
Now follow these instructions to export from iCloud: Export and Import from iOS/iCloud.
Alternatively, you may use Apple's instructions to export from the Contacts app - make sure to choose the VCF option.