You can use the Lock library to define, add, read, and update the user_metadata. You can read the user’s user_metadata properties the same way you would read any other user profile property. For example, the following code snippet retrieves the value associated with user_metadata.hobby and assigns it to an element on the page: 
// Use the accessToken acquired upon authentication to call getUserInfo
lock.getUserInfo(accessToken, function(error, profile) {
  if (!error) {
    document.getElementById('hobby').textContent = profile.user_metadata.hobby;
  }
});
You can use additionalSignUpFields to add custom fields to user sign-up forms. When a user adds data in a custom field, Auth0 stores entered values in that user’s user_metadata. To learn more about adding user_metadata on signup, read Additional Signup Fields.

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