Add mobile number condition and minimum characters in message

Hello,
I am new to WP and this plugin.
I’ve created a form using contact form 7.
I want to add conditions for the following.
1. valid email address – in correct form i.e [email protected] format
2. valid mobile number – only numbers and only 10 digits
3. minimum 20 characters in the message field.

Thank you for your help 🙂