Share a single calendar with iCloud
If on mac:

Open up calendar app.
Right click on the specific calendar you want to share with someone.
Click on &quot;Share Calendar...&quot;
Write the name of iCloud user you want to share that calendar with.

If on ios:

Open up calendar app.
Find the calendar you want to share.
Press the &quot;i&quot; icon aligned at the right of each calendar.
Click &quot;Add Person&quot; and write your friends iCloud adress, name, whatever..

I gotta mention it mainly works on iCloud calendars, not for lets say &quot;Google&quot; account's calendar.
I hope it helps, feel free to comment here if you got any more question.