Prefill the subject manually

See https://contactform7.com/text-fields/

Tx Takayuki.
I’ve tried [text* your-name class:required “John Smith”] but the visitor can overwrite on it, no way to avoid this to keep the defaut value as fixed?

In the first place, you don’t need to set it as a field value if you disallow visitors to change the value.

So what should I enter to display a fix subject please ?

See Setting Up Mail

Enter text as you like in the Subject field.

I don’t think we understand each other, I’m still speaking about the form, not the email send. Anyway, I’ve entered the subject in the form, the user can still overwrite it but if there’s no solution to fix it, I let it like this