Checkbox in user edit page I have customized the user-edit page in Drupal7 using user-profile-edit.tpl.php.  I have also added reCAPTCHA to it using the reCAPTCHA module. 

I would also like it so that there is an "I agree to terms and conditions" checkbox, and only when the user clicks this check box should the information be saved (i.e, it should be a required field). 

How can I do that? 

I found the Terms of Use module and the Legal module but they appear only on the registration form, whereas I want it in user-edit page (form). I thought of adding a field to the account settings for users but I am not getting any desired field for that. 

Any suggestions?

Following the answer below, I was able to do some progress. However I want it to be a required field and if I click on that in its field setting then automatically it is shown on the user registration page which I do not want .
You can select the Boolean field and widget type as Single on/off check box...This should solve your problem...No need to use any modules