title: Create user custom attribute for whole B2C instance via graph api or graph sdk
body: <p><strong>I want to create 'user custom attribute' for whole b2c instance via graph api or sdk. Just like I do thru Azure Portal following ms <a href="https://docs.microsoft.com/pl-pl/azure/active-directory-b2c/user-flow-custom-attributes?pivots=b2c-user-flow#create-a-custom-attribute" rel="nofollow noreferrer">documentation</a> quoted below.</strong></p>
  <pre><code>1. Sign in to the Azure portal as the global administrator of your Azure AD B2C tenant.
  2. Make sure you're using the directory that contains your Azure AD B2C tenant by switching to it in the top-right corner of the Azure portal. 
  3. Select your subscription information, and then select Switch Directory.
  4. Choose All services in the top-left corner of the Azure portal, search for and select Azure AD B2C.
  5. Select User attributes, and then select Add.
  6. Provide a Name for the custom attribute (for example, &quot;ShoeSize&quot;)
  7. Choose a Data Type. Only String, Boolean, and Int are available.
  8. Optionally, enter a Description for informational purposes.
  9. Click Create.
  </code></pre>
  <p>Just to be clear I don't want to create user with custom attribute, but a custom attribute for all users in b2c.</p>
  <p>Can I do it and if yes how?</p>