Add or delete calendar accounts on Mac
If you keep calendars in internet accounts — for example, iCloud, Yahoo or another CalDAV account — you can use the accounts in Calendar on your Mac, and access all your calendars and events in one place.
Add a calendar account
In the Calendar app
on your Mac, choose Calendar > Add Account.Do one of the following:
Select your calendar account provider, click Continue, then follow the onscreen instructions.
If your calendar account provider isn’t listed, ask your provider for the information you need to enter.
Choose Other CalDAV Account, click the Account Type pop-up menu, then choose an option based on the information you need to enter.
Automatic: Choose this option if you just need to enter your email address and password.
Manual: Choose this option if you need to enter your username, password and the server address.
Advanced: Choose this option if you need to enter your username, password, server address, server path and port number. You can also select tickboxes if you need to use SSL or Kerberos v5 authentication.
Each account you add is listed separately in the sidebar. If the sidebar isn’t showing, choose View > Show Calendar List or click the Calendar List button 
in the toolbar.
Set up your iOS and iPadOS devices to use the same account, so that your calendars stay up to date across all those devices and your Apple Watch.
Stop using a calendar account
You can temporarily stop using an account so that its calendars and events no longer appear in Calendar on your Mac.
In the Calendar app
on your Mac, choose Calendar > Accounts, then select the account you want to stop using.Deselect the Calendar tickbox.
To use the account again in Calendar, select the Calendar tickbox. The account’s calendars and events reappear.
Delete a calendar account
If you no longer want to use an account in any app, including Calendar, you can delete the account.
Note: If you use iCloud Keychain and you remove an account (other than your primary iCloud account), you’re asked whether to remove the account from your other Mac computers that use iCloud Keychain, or just turn off all the account features on this Mac.
In the Calendar app
on your Mac, choose Calendar > Accounts, then select the account you want to delete. Click the Remove button
at the bottom of the account list.
You can view, add and modify events, and respond to invitations, in the Calendar app on all your devices that use the same accounts. You can also view, add and modify your iCloud calendar events, and respond to invitations, on iCloud.com. Changes you make show up everywhere, so you always have your most current calendar events at hand. Calendar notifications also appear on your Mac and other devices that use the same accounts.
If you use Handoff, you can switch between your Mac and other devices while creating, modifying or viewing events and calendars. To open an event or calendar handed off to your Mac, click the Handoff Calendar icon that appears at the left side of the Dock.