This article contains the steps to publish a Sharing URL in Exchange Online
Do your users want to share their calendar with anonymous users? Here's a tip related to sharing your calendar via a web link for anonymous users (users outside of your organization). Users can publish their calendar for anonymous viewers using OWA. Organization administrators can also publish a user's calendar. Here we will share both of those ways.
Note: Publishing your calendar for anonymous users allows anyone with the link to the calendar to view it without having to log-on.
Publish your calendar using OWA
Publishing your calendar: Log on to OWA and go to Calendar. Right click the calendar you want to share and choose permissions:
Change the permissions drop-down from “Not Shared” (Default) to “Availability only” (or whichever permission you intend to grant) and press Save:
Retrieve the link to share it with users outside of your organization: Right click Calendarpermissions > and then View Calendar. This will bring up a browser window with the sharing link (URL). You can also right click on the View Calendar link and then select Copy Shortcut to get copy the link. You can send the link to users outside your organization to allow them to view your calendar
Publish a user's calendar (as an organization administrator):
If you're an organization admin, here's how you can publish the calendar of a user or a resource/room using PowerShell.
Run Set-MailboxCalendarFolder <Username>:\Calendar -PublishEnabled $true
Run Get-MailboxCalendarFolder <Username>:\Calendar |fl or Get-MailboxCalendarFolder <Username>:\calendar |fl publishedcalendarurl. This will output the published calendar html (and ics) urls. Others can use this url to view the publisher’s calendar.