So you are using SendGrid option to send a form on form submission, which you can change the email if you go into SendGrid and set it all up yourself.
However, the easier option would be to just use triggered emails and set yourself up a triggered email which gets sent to either the contact or the member after a form is submitted.
You can brand this yourself etc and put whatever variables you want on the email too.
https://support.wix.com/en/article/about-triggered-emails
https://support.wix.com/en/article/creating-a-triggered-email
https://support.wix.com/en/article/corvid-tutorial-sending-a-triggered-email-to-members
https://support.wix.com/en/article/corvid-tutorial-sending-a-triggered-email-to-contacts
For the email just simply back to yourself, then you can simply just do a Wix Automation and include the details of the form etc.
https://support.wix.com/en/ascend-by-wix/wix-automations
https://support.wix.com/en/article/creating-a-new-automation
Select the Include details toggle if you want to receive details such as what data was collected or what was purchased.