Instagram does not notify someone if you screenshot their story, allowing users to view and capture stories without alerting the original poster.
Instagram tested a feature to notify users about story screenshots in 2018 but removed it following user feedback.
While regular story screenshots go unnoticed, Instagram does send a notification if someone screenshots a disappearing photo or video sent via DM.
It is essential to remember that once content is shared online, there is always a possibility of it being saved or screenshotted, highlighting the importance of sharing content cautiously.