On your iPhone or iPad, open the Settings.

Select Passwords & Accounts.

Select Add Account from the bottom of the list.

Enter your Google Account email address and password. If you’ve set up two-factor authentication, you’ll need to log into your account to set up an app password and use that as your password when you set up the account in iOS.

Tap Save and wait for your calendars to sync with your iPhone. Depending on the size of your calendars and the speed of your connection, this process can take several minutes.

Open the Calendar app.

At the bottom of the screen, tap Calendars to display a list of all calendars to which your iPhone has access. It’ll include all of your private, shared, and public calendars linked to your Google Account.

Tap the circled red i beside the calendar name to change the default color associated with the calendar or even change its name, then tap Done at the top of the screen.

Select or deselect the individual calendars you want to appear when you’re accessing the iOS calendar app.