Good evening, @chowdhmj1993 Welcome to the Canvas Community. Thank you for posting your question. Canvas does not have a "Dropbox". This terminology might be used in other LMSs, but not in Canvas. You can submit multiple files to one assignment in your Canvas course, however. Please check out this Guide: https://community.canvaslms.com/docs/DOC-10663-421254353 Check out the illustration under the heading "Add Another File" (about half-way down that page).
I hope this information will be of help to you, Misbahul. Please let Community members know if you have any other questions about this...thanks!