Hello Vladimir,

Please follow below steps to create & configure an Azure app and Outlook Calendar in Odoo.

Steps to create Azure app.

Step 1: Open 'Azure Active Directory' in Microsoft Azure portal.
Step 2: Go to app registration menu and register a new application.
Step 3: Fill Application name, select supported account type(All Microsoft users) and add Redirect URI.
Step 4: In Certificate & Secrets create new client secret, fill the client secret description and expiry limit for client secret.

Steps to configure outlook calendar in Odoo.

Step 1: Install ‘Outlook Calendar’ module and go to settings -> General Settings -> Integrations
- Enable ‘Outlook Calendar’ and add client id & client secret value.
Step 2: Go to Calendar and synchronise the Outlook calendar by clicking on ‘OUTLOOK’ button.
- Upon clicking it you will redirect to Microsoft account login page for authentication, login here and give permissions to read and write calendar events and other.
- Your events will synchronise with Outlook calendar.

Note:
- Select supported account type (All Microsoft users) for application
- No need to add permissions for app.
- Check for in Settings-> Technical -> System Parameter menu and then find for the parameter “microsoft_redirect_uri”
and prepare a URL as shown : (web.base.url of odoo) + ‘/microsoft_account/authentication’

Where “web.base.url” is another System Parameter which is concatenated with a controller “/microsoft_account/authentication” 
For eg. : web.base.url is http://localhost:8069
therefore the prepared url will be: http://localhost:8069/microsoft_account/authentication

Add this prepared url to System parameter ‘microsoft_redirect_uri’ and Azure app Web Redirect URIs.
- Configure Outlook calendar to synchronise events from User -> Calendar page with ‘Reset Account’.

You can refer below link to create Azure application.
Link: https://apps.odoo.com/apps/modules/16.0/ak_odoo_teams_integration/

I hope this will help you.

Thanks & Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari