What to do if the length of the key does not divide the length of the plaintext in Vigenère Cipher?

What to do if the length of the key does not divide the length of the plaintext in Vigenère Cipher? In this video, we are going over padding. Note that the concept of padding is not specific to Vigenère Cipher. There is a challenge for those who are interested. Watch until the end! This video complements the introduction to Vigenère Cipher: https://youtu.be/Z3FwEqq12Sw Thanks for watching!