Contact Form 7 can be customized in two ways, no need to change any code.
1- Theme Options – ( Globally for Whole Site Contact Form 7 )
https://apressthemes.com/help/docs/contact-form-7-options/
2- Page Builder Element – For Individual / specific Contact Form in pages / posts
https://apressthemes.com/help/docs/contact-form-7-element-options/
Note – If styling is applied to a Contact Form using Page Builder Element then it will override the Theme Options Contact Form7 Settings will.
