How can I add a checkbox to confirm users want to sign up for a newsletter?

on my form i would like to set it up so isers are automaticvally signed up for newsletter with option to switch it off?

You can try any of the following integrations available in your form to collect email addresses from your respondents.

I suggest that you try MailChimp as I believe it has the options you need to meet your requirements.

How-to-Integrate-with-MailChimp

I hope this helps. If you have other questions or concerns, please do not hesitate to let us know

thanks ive added the integration for campaign monitor but still dont qiute understand how i can now add an option for people to choose to be on the newsletter list???

actually think ive cracked it now but can i edit any of the text or titles around the newsletter on my form??? - https://www.flyingkiwi.com/competition

Yes, this is possible, you can edit the titles and text from within the form builder. A simple way to make edits is to apply a theme to your form.

Alternatively, you can make edits by selecting a form field and clicking the Properties or Settings icon to view various editing and design related options. 

There is also a form designer tool to make changes to the overall design of the form, click the paintbrush icon in the top right corner to access these options.

Do let us know the specifics of what changes you need to make so we can provide further assistance.