sql server giving error : is not a recognized function name
Make sure you are executing it in the correct database context.
If the view is in Database2 and the function is in Database1 then you will need to fully qualify the function using the three part name:
Database1.dbo.[Function_Name]
All objects in a view are assumed to be in the same database as the view unless you specify otherwise.
Is the view on the same database as the function? If they are not, you need to call it like [database_name].dbo.[function_name]