hi Boopathy....
i have read your post, and i can create the application, i will create your application using react native so you can using both for android and ios, you can download file facility as PDF, for backend service i will create using php and mysql, i can create your application with at most 14 days from the project accepted, you will not regret with my application, because its easy to use, and within fastest execution time.
thenks, Robet...