To change the number or add a social media URL to your WordPress website, please follow the below instructions -

Step 1. Login to your wordpress account.

Step 2. On the left menu > go under Theme Settings and there is a section for "Contact information" and "Social Icons"

The icon code comes from here: https://fontawesome.com/v5.15/icons?d=gallery&p=2&m=free . Click on the icon you want to use and you can copy its code like -