LiveSplit is a time spliter for speedruning. It's not obligatory but I recommand you to use it if you want to beat your times !

LiveSplit doesn't exist on smartphone but you can add the timer with a video compilation easily.

You can upload your LiveSplit files on the website : https://splits.io/ and then import your split on speedrun.com with your run. It's easier to verify runs and other players can use your splits in their trainings !