With the update of DIVI theme to the new 3.0 with visual editor, another change appeared: a footer which seems like it cannot easily be changed to credit you or your company.  This assumption is wrong.

Correct Way To Change It

Login to your admin panel and in the left navigation go to –

DIVI > Theme Customizer > Footer > Bottom

You can either disable the credit or use the box to write-in your own. Save.

 

Alternate Method

Simply copy and paste an older DIVI (2.x) footer file over or portions of the file.  Of course, you will want to use the method above over this method so that you can easily use the DIVI editor to update it in the future.  This second method may be best in a situation where you are designing the site for a client and you do not want them to change the footer with the easy to use tool.