They both are from the same root word. They come from the Latin word destinare which means to stand resolved, determined, secure.
However, destiny implies a fate we are assigned. But destination suggests a goal we are striving for. Could it both can apply in our lives?
We may not know the future and what blessings and hardships await us. But we can also work toward a goal that shapes our future. After all, what we do today can shape our future for good or for ill.
While we cannot fully know our destiny, we can have a destination. Both are valid.