1. I added [share] shortcode in Text widget and drag it to “Place in header top bar” area in Appearance > Widgets.
Now i see 4 social icons in my menu bar. How can i custom it and just let the facebook icon and delete the 3 others?
2.Moreover, where can I custom the facebook link and put my facebook page beside it?
1) Code of [share] shorcode you can find in \wp-content\themes\royal\framework\shorcodes.php. (lines 1727 – 1770). Please do all your changes in the child theme to avoid problems with next theme update
2) It’s possible to implement only by additional customization if you have appropriate skills. Additional customization is beyond the scope of our support.