Hello,
1) Go to Contact > Contact Forms > edit the contact form from the contacts page and change the default information according to your site content https://prnt.sc/NmJBAX5XlbF7
Also, go to Settings > General > edit the site title, tagline etc
2) Install reCaptcha for the contact form 7 to avoid spam messages https://contactform7.com/recaptcha/
Regards