How does "handoff" work between the iPhone and Macbook with the Messages app?

I thought that if I were in the middle of typing a text message on my iPhone, the handoff feature would allow me to open and resume the actual message from my Macbook; however, today it appears to only open the app to a blank message on my computer and vice versa--ultimately making this feature useless. It appears to be functioning properly in regard to Chrome. Can someone please let me know if this is how it normally operates, or if it is actually malfunctioning? I appreciate any help.

Thank you,

Ryan