To sync Calendars for Mac with an Outlook account, tap Outlook when launching Calendars for the first time, then follow the onscreen instructions. And here's how you can add an Outlook account later on:
- Open Calendars.
- Tap the three-lines icon in the top left corner (skip this step on your iPad).
- Go to Settings > Accounts.
- Select Outlook and log in with your Outlook account credentials.
- Open the Calendars app.
- Click Calendars in the Menu Bar at the top.
- Select Preferences > + Add Account button.
- Click Google and follow the onscreen instructions.
If this is a work Outlook/Exchange/Office 365 account, check with your system administrator to make sure the Calendars app is allowed to access your account.