To check for files in folder: item.Contains("~$")

HI I am doing a code set up to check for if file exist in a folder

The already code has a loop for Each file in a folder
Can someone explain the meaning of

item.Contains("~$")

here the argument type is String
in layman terminology.

Use Path Exists activity and its boolean output will tell you whether your file exists or not.
You just need to add Path Exists activity in your Sequence and provide the File Path and Path Type in properties of the activity.