Twitter is rolling out the new content warning feature for all users. The social media platform was testing this feature last year, and it is now available on both Twitter's Android and iOS apps as well as its web client.
The option to add one-time sensitive content warnings to photos and videos you Tweet is now available for everyone across Android, iOS, and web.
— Twitter Support (@TwitterSupport) February 25, 2022
To add a content warning, tap the flag icon when editing the photo/video after you've attached it to your Tweet.
The feature allows users to hide individual photos and videos behind warnings for "violence," "nudity," or "sensitive" content. Previously, users who wanted to flag potentially sensitive content in their tweets only had the option of adding a general warning to all multimedia tweets.

To put a content warning on multimedia, the user should tap the flag icon when editing an attached photo or video in a tweet and apply a specific category to that warning. Several warnings can be tagged for individual photos or videos, and a warning can be added to one video or photo in a tweet. However, Twitter will still put a single content warning over both pieces of media.
People use Twitter to discuss what’s happening in the world, which sometimes means sharing unsettling or sensitive content. We’re testing an option for some of you to add one-time warnings to photos and videos you Tweet out, to help those who might want the warning. pic.twitter.com/LCUA5QCoOV
— Twitter Safety (@TwitterSafety) December 7, 2021
Content warnings cannot be put on text tweets. As before, Twitter users can click through the warning to view the photo or video.
The idea behind content warnings is to help people avoid interacting with potentially upsetting media and disturbing and unsafe content.