Choose the permission level based on how much they actually need to see
Outlook offers several sharing levels, from showing only whether you're free or busy up to full event details, so you don't have to expose every meeting title and description just to let someone check your availability. Picking the narrowest level that still meets the purpose -- often just free/busy for scheduling -- keeps more sensitive calendar details private by default.
Sharing outside your own organization usually needs extra steps
Sending an invitation to an external email address, such as a client or an outside collaborator, generally works the same way, but an organization's administrator may restrict or require extra approval for external calendar sharing depending on company policy. If an invitation to an outside address doesn't seem to go through, checking with an IT administrator about the organization's external sharing settings is a reasonable next step.
Frequently Asked Questions
Can I share my calendar with someone outside my organization?
Yes, you can share with an external email address, but an administrator's policy may restrict or limit external sharing depending on the organization's settings.
Can I change someone's permission level after sharing?
Yes. You can adjust their permission level or cancel the sharing entirely at any time from the calendar sharing permissions screen.