Ooops!
It’s easy… if you have Apache installed then it means it’s not in your path. Did you complile your Apache yourself? If so it should be here:
/path-to-your-apache-folder/bin/htpasswd
Want to add it to your path:
PATH=$PATH:/path-to-your-directory
Or create a .bash_profile in your home directory and add that variable there, then execute
source ~/.bash_profile
Works for everything else as well!