I'm wondering what the best way or what way I should do this.
https://www.example.com is in the directory /home/examplesite/www
https://www.example.com/contactus is in /home/contacts/docs
Assuming this is Linux, and you're not using a control panel, you could use a symbolic link here. It requires having the right permissions in both, and AllowSymlinks (I think) being setup in the apache configuration, but as far as I'm aware this is usually default for vhosts. Simply:
Actually the proper Apache method / approach would to be use an Alias instead of maintaining symlinks
Alias /contactus /home/contacts/docs
It all depends on how you want to do it.. (from the OS, or from Apache)
Hope this helps :D