How can I include the Text Fields on email templates?

We are using a one of your contact form templates as our contract. Currently clients fill in their names and event date. They then tick to acknowledge their agreement to the terms and conditions we have listed as text in the form.

After submission, we and the clients only receive back the parts they have entered and the ticks of acceptance, but the text is stripped out.

We really would like to know how to have it so that the entire form, including the text that we had as part of the contract is sent to both us and them.

You're probably referring to the Text Fields on your form. These are not included on your email template by default since these are not Input Fields. To include them, you'd have to manually copy and paste them to your email template.

Complete guide: How-to-Edit-the-Email-Template-for-Notifications-and-Autoresponders 

And since we're already talking about Text Fields, should you wish to include them on the PDF Submission too, refer to the guide I'm linking below.

Related guide: How-to-Show-Headers-and-Text-in-the-PDF