Use information found in Mail in other apps on Mac
When you receive email messages that include invitations, dates, times, addresses, phone numbers and other types of information, you can easily use the information in the Calendar and Contacts apps.
Add events to Calendar
In the Mail app
on your Mac, select the message that contains the Siri Suggestion.Click “add” to review the suggested event (you can customise the event by clicking Details).
Do one of the following:
Accept the suggestion: Click Add To Calendar.
Decline the suggestion: Click the Close button
or click Ignore.
If you want Mail to automatically add events for you, choose Mail > Preferences, click General, then select Add invitations to Calendar automatically.
For an Exchange account, add events using buttons in the banner at the top of the email. Click Accept, Decline, Maybe, or OK (for cancelled events). Your reply is sent to the event organiser and your calendar on the Exchange server and in Calendar is updated when it syncs with the server.
Add people to Contacts
In the Mail app
on your Mac, select the message that contains the Siri Suggestion.Do one of the following:
Accept the suggestion: Click Add (you can review the information before adding it to Contacts).
Decline the suggestion: Click the Close button
.
There are other fast ways to add someone to Contacts:
In an email you receive, move the pointer over a Smart Address, click the arrow that appears, then choose Add to Contacts.
In the message list, select a message, then choose Message > Add Sender to Contacts.
If you don’t want Siri to make suggestions in Mail, choose Apple menu 
> System Preferences, click Siri, click Siri Suggestions & Privacy, then unselect the Mail tick box. If you change your mind later, select the tick box.
You can add events and information to Calendar and Contacts yourself. Move the pointer over a date, time, phone number, email address, or street address until an outline appears, then click the arrow to take an action.