Within the Twitter Ads UI (ads.twitter.com), log into your ads account and click Tools > Conversion tracking.
If prompted, generate your new Universal Website Tag. Otherwise, click “View code and installation instructions”.
Within the code snippet, copy your pixel ID from the line that resembles “twq(‘init’,‘twitter_pixel_id’);”. In the screenshot below, the pixel ID is ‘31vgl’. Your pixel ID will be unique to your ads account.