The best way to give access to your Virto calendar is through SharePoint. You can add an external user to your SharePoint site and provide them access to view or edit the calendar there.

First, go to the SharePoint site you want to share.

Once there, click the "Members" button.

Then, click "Add members". Find the "go to Outlook" hint In the pop-up and click on it.

In your Outlook that opens, click "See all members."

Then, click "Add members" on the right side of the screen.

Provide the email address of the external user with whom you wish to share the site. Click "Add" once done.

The external user will receive an email invitation to access the site (by clicking "Go to SharePoint" in the email).

They must log in with their email, enter a single-use code sent from Microsoft via email, and accept the permission request.

Users can view the site and its content, including calendars hosted on this particular site.

To add SharePoint events to your Outlook calendar, create an iCalendar (.ics) file to add the event to Outlook.

To do it, select the event and click the “Add” icon on the bottom left of the event card.

Save the automatically generated .ics file. Next, open Outlook and click the “Add calendar” button.

Then, select the “Upload from file” option and drag and drop your event file into the designated area. From the dropdown menu, choose the calendar to which you want to add your event and click “Import.”

The chosen event will appear in your Outlook calendar with the same data as in the Virto calendar. In this way, the team members can add any events they wish to see to their Outlook calendar.