Anil,
I assume you are an instructor and talking about a file you deleted from a course in Canvas. There is a sort of undocumented method that an instructor can use to undelete content from a course. It works most of the time and I've provided a link to a write up about how to use it.
https://community.canvaslms.com/groups/admins/blog/2015/04/22/undeleting-things-in-canvas
Rick
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