I have found https://balsamiq.com/ https://balsamiq.com/ to be a great way to move fast; I prefer to work at first in the 'cartoony' mode of crooked lines etc..

I have found https://balsamiq.com/ https://balsamiq.com/ to be a great way to move fast; I prefer to work at first in the 'cartoony' mode of crooked lines etc.. then present straight edged wire frames to the stake holders.