Custom submit button

See Submit Button

You can use the class option (class:btn-custom).

Thanks for the reply.
I’ve tried this code and several variations to the form builder admin page but the custom button format doesn’t apply.
<p>[submit class:btn-custom "send mail"]</p>
Am I meant to paste my btn-custom code into one of the CF7 php files?
Or something else?
And if you update the plugin will my php changes be affected?
And if so should I create a child file or something?

See Getting Started with Contact Form 7 for basic usage.

Thank you for not being very helpful. I think I’ll try another form plugin.