For glowing decorations, moving lights and costumed street scenes, try a Live Photo instead of a conventional still. Apple’s Photos app can turn a Live Photo into a simulated long exposure by combining its brief motion sequence. It is a quick experiment that does not require RAW processing or a tripod-mounted DSLR.
Take the Live Photo while keeping the phone as steady as possible. In Photos, open it, tap the Live control and choose Long Exposure. Compare the result with the original. It works best when a moving subject leaves a trace against a relatively still background; it will not rescue every low-light photo.
The practical test is one shot of moving Halloween lights and one of a static decorated house. Save the better version and avoid applying the effect indiscriminately.
Go to Source — https://support.apple.com/guide/iphone/edit-live-photos-iphd8dbb3291/27/ios/27