Hello - Can this page be customized? As you can see, they're asking me to set default values...

not sure might not be customizable

Pages like these generally are not.

@JC Depends on how you load the page. Hypothetically, you could create a suitelet with a link to this page and when a user clicks that link, the link could have some parameters potentially that would set values on that screen. So, you can't exactly customize that page...but you can customize links to that page

See that big button on the left that says...Customize?