To add a Contact Us form in Drupal you need to follow the following steps:
1. You need to enable the conatct module from here admin/modules
2. Navigate to admin/people/permissions and select the checkboxes under Contact next to the "Use the site-wide contact form" permission for the roles you want to have access to the contact form
3. Scroll down and click "Save Permissions"
4. Navigate to admin/structure/contact and click edit next to the "Website feedback" category
5. Modify the category name and recepient email according to your site and save the form
6. Now logout and navigate to /contact and you should see the contact us form
I hope you've enjoyed this tutorial and stay tuned for more to come