You can allow your members to sign in to your community using their Microsoft account.
To start the process, go to AdminCP -> System -> Login & Registration, click Create New to setup a new login method and choose Microsoft. You will now be prompted to fill in some details which you'll need to acquire by creating an "app" with Microsoft.
Creating a Microsoft App
1. Go to the Microsoft Azure App registrations page and sign in with your Microsoft account.
2. Click New Registration and fill in a name (just use the name of your community).
3. Unless you have a specific need to change it, under "Supported account types" leave "Accounts in any organizational directory and personal Microsoft accounts (e.g. Skype, Xbox, Outlook.com)" selected.
4. Under the field labelled Redirect URI, leave the dropdown selected as "Web" and then enter the value shown in your AdminCP into the text field. You must then click Register at the bottom to save this.
5. Copy the Application (client) ID shown on this page into the AdminCP under Application Id.
6. In the Azure App registrations page for the application you just created, click Certificates & secrets in the left hand menu. Click the New client secret button. Set the secret to Never expire, provide an optional description, and click the Add button.
7. Copy the value displayed on the Certificates & secrets page after adding a new client secret and paste it in to the AdminCP as the Password.
8. Finish creating the new Login Method and verify you are able to successfully log in to your community using a valid Microsoft account.