Hello @A.M.M.Sajeeth,
I can see in the UI, the Blood_Bank > Users collection is opened.
Possibly you have selected a different database in the shell. you can execute db command and it will show the current selected database.
You can change the database in the shell by use <database name> and then you can execute your query.
Note: The collection name is case-sensitive, so
Usersandusersare both different.