Here's how you (and your students) can add preferred name and make other customizations to the way your name is displayed in Moodle (such as adding preferred pronouns):
1. Open your Moodle Profile:
2. Select Edit Profile:
3. Type to add the preferred name to the Preferred name field:
4. Scroll to the bottom and select Update Profile:
Your Moodle Profile will be updated to display your preferred name.