If the secondary menu is enabled, it can display the social icons.
Fist please, add your links:
- in appearance > customize > social, add the links to your social profiles
- Publish
To enable social icons in secondary menu
- In appearance > customize > header and menu > secondary menu > ENABLE the secondary menu
- then go to Customize > header and menu > social
- Enable social in "Secondary header"
- Now you can set the design for your social icons
- Click Publish
