By default, the Submit button on a Contact Form module is placed on the Right and has a fixed width.
Using a custom CSS code, we can set the submit button width to be full width.
Setup the Contact Form module
Open the Contact Form module's settings by clicking on the Gear icon
Go to Advanced Tab → Custom CSS → Free Form CSS
Add this CSS Code:
selector .et_contact_bottom_container {
width: 100%;
flex-direction: column;
gap: 1em;
padding-left: 3%;
margin-top: 0px;
}
selector .et_contact_bottom_container button {
width: 100%;
margin: 0;
}
The result would be as per the screenshot below:
