For TikTok, you need to manually add UTMs to the destination URL that you enter in the “URL” field of the “Destination page” section, when creating/editing a TikTok ad.

• If you already have URL parameters at the end of the destination URL, paste the following at the end of the URL.
  
  &socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__
  
  Make sure to also include the ‘&’ operator and that there is no ‘/’ or ‘\’ at the end.Eg. If your destination is www.examplestore.com,
  CORRECT:
  www.examplestore.com/?existing_utm=value&socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__WRONG:
  www.examplestore.com/existing_utm=value/&socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__NOTE: The double underscores are correct and that is what TikTok supports. Do make sure to include them as they are above. Also do ensure that there is ‘/?’ where your URL ends and your UTMs start.
• If there is no parameter toward the end of your destination URL, paste the following text:?socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__
  
  Eg. If your destination is www.examplestore.com,
  CORRECT:
  www.examplestore.com/?socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__WRONG:
  www.examplestore.com/socioh_tid=tiktok:__CAMPAIGN_ID__:__AID__:__CID__:__PLACEMENT__