Hi,

Social Icons are based on Font Awesome 5.15.2 - and as I know it doesn't have "Tripadvisor" icon becuase of the law limitations. Also in FA 6.x it still doesn't have it.

so you have to use extra CSS tricks to display that icons. In general it's task beyond support, so I can give you only basic tips how it may be done:

1. Find "Trip advisor" logo - white/light grey color of icon, transparency background, 16px of height. Or use Photoshop to correct size, color etc.
2. In Template Options > Basic > Social icons - put needed URL to one of social icons, for example, "flickr".
3. Then upload "tripadvisor" logo image (png/gif/svg) to folder /images/
4. Use custom CSS that will replace "flickr" icon with image of "tripadvisor". Example code

.social-icons .fa-flickr::before {
  content: url(/images/tripadvisor.png);
}