Open Google Calendar
Click the gear icon
Select Settings
Under “Settings for my calendars,” click the calendar you want to share
Go to “Share with specific people and groups”
Click Add people
Enter the person’s Google Account email address
Choose their permission level (See only free/busy, See all event details, Make changes to events, or Make changes and manage sharing)
Click Send
(Optional) To share with a wider audience, under “Share with specific people and groups,” use “Get shareable link” and set access permissions
(Optional) To share with a public link, adjust “Access permissions” to the desired public setting and copy the link