Open the Mail app on your Mac
Click Mail in the menu bar
Select Settings
Click Accounts
Choose the mail account you want to check
Open Contacts app to view saved mail contacts
Use Spotlight Search and type Contacts
In Contacts, search by name or email address
Open Mail and start typing in the To, Cc, or Bcc field to see suggested contacts
Click Window in the Mail menu bar
Select Previous Recipients to view email addresses used in Mail
Open the Contacts app from Launchpad or Applications
Check the Groups sidebar in Contacts to view contact lists
Use the search bar in Contacts to find specific mail contacts