title: Allow user to access shared mailbox using Graph api in c#
body: <p>Currently we are adding users to requested shared mail box using PowerShell in c#. Due to basic AUTH going to disable, now we are planning implement using Graph api.</p>
  <p>This how I thought to implement,</p>
  <ol>
  <li>Get the requested user details using  Graph api</li>
  <li>Get the requested shared mail box details from Graph api</li>
  <li>Add the user to requested mail box.</li>
  </ol>
  <p>Here I am able to get user and requested mail box but not sure how to add the user to shared mail box.</p>
  <p>I am accessing all the details using service account and following App permission method.</p>
  <p>Below are the code to get user and mail box,</p>
  <pre><code> var options = new TokenCredentialOptions
              {
                  AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
              };
  
  var clientSecretCredential = new ClientSecretCredential(
                  tenantId, clientId, clientSecret, options);
  
  var graphClient = new GraphServiceClient(clientSecretCredential, scopes);
  var requestedDetails = await graphClient.Users[&quot;emailaddress&quot;].Request().GetAsync();
  </code></pre>
  <p>Is it possible to achieve this using Graph api? if yes then which endpoint I should call?</p>