This post explains how to enable logging of basic user statistics whenever a form is submitted.
Visit the USP Pro General settings and enable “Enable Basic Statistics”.
There is no step 2. After enabling the basic-stats setting, USP Pro automatically will collect user data such as IP Address, User Agent, Referrer, and Request URI. This data will be attached to each submitted post as Custom Fields.
Viewing the data
To view the collected user stats, visit the “Edit Post” screen for any submitted post and click the “Screen Options” button in the upper-right corner of the screen. There you can check the box to enable the “Custom Fields” meta box. After doing this, you can scroll down the page beneath the post-content field and toggle open the “Custom Fields” panel. There you should find custom fields similar to the following:
usp-address => 123.456.789.0 usp-agent => Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36 usp-referer => http://example.com/?usp_form=submit usp-request => http://example.com/?usp_form=submit
These custom fields can be used anywhere in your theme, or in plugins, etc. They are very versatile, enabling you to make use of the collected data however is desired.