The administrator can define the following settings.
They can be access via the admin menu: Apps → Outlook Meeting for Jira/Microsoft 365 for Jira → Outlook Meetings settings/Meetings settings
Configure Preferred Messaging / Call Client
If your organization is still using Skype for Business exclusively, you can specify this here. It will then adjust all call & send message links in the user actions to use Skype for Business instead.
Online meetings are only supported when using Microsoft Teams
Enable Online Meetings with Microsoft Teams
An Office 365 administrator can authorize the app to allow creation of online meetings. Without this authorization the app will not be able to create Teams meetings - all other features like showing availabilities and sending meeting requests are unaffected.
Custom AzureAD App Registration (Jira Server only)
If you want to use a custom app registration, you can do this via the “Advanced Connection Settings” dropdown. Please see this article on how to configure this feature.