How do I get the text box to show up on the email that is generated once you submit the form?

What is the form you are working on? If you have added a new Text Box field in your form, and it's not showing in you current email notifications, there are two ways to include it:

1) Delete your current notification and create a new one: https://www.jotform.com/help/25-Setting-Up-Email-Notifications 

2) Edit your existing notification an manually add the field into your compose email:

In the form builder, click the "Emails"  button on the form builder toolbar:

Hover your mouse to the notification and click the edit in pencil icon:

Include the new row, and the field of your form, make sure to click on Finish an Save your form:

Let us know if you need more help, we will be glad to assist you.