The first method is to use pinch zoom, a common gesture on most touchscreen devices. You can place two fingers on the image and pinch them together to zoom in, or pinch them apart to zoom out. This method works for photos and videos in the feed, profile, and direct messages.
You can also zoom on Instagram Stories by simply sliding two fingers across the screen. This allows you to take a closer look at stories and explore details.
While with live videos you won't be able to zoom into the video itself, you can zoom in on the comments section to better see the interactions. Just double-tap the comments section to enlarge it.