Your program must have one function method that returns the sum (in binary as a string), given the two numbers (in binary as strings).
Good solutions may have even more functions.
Your program may have a text or graphical user interface.
Hint: The obvious strategy of converting both strings to numbers, adding them, and converting the sum to a string will take more time than a stragegy that just works with the characters in the strings and will not be able to cope with very large binary numbers. The all-character method should be able to cope with very long numbers.
The even more obvious answer is that if you are posting such simple homework assignments to forums (without even making a pretense at asking a legitimate question), you need to change your major.