I have updated all of my Wordpress plugins and I'm using the Hello Elementor theme as recommended.
In Chrome all of the information is saved in the forms, and in Iphone Safari all info is saved apart from the customer's name. This information is visible to the next person who visits the checkout page.
This is a big breach of privacy. Is there a way I can fix this?
I think you may be confusing where the user specific information is stored. Both Chrome and Safari have autocomplete features that save user specific information on their device so the user doesn't have to re-enter their own name or address. Because that user specific information is stored on the device, other users on different devices don't see that stored information.
To test this out, you can disable autocomplete by modifying the HTML. Here is some good documentation on disabling autocomplete: https://developer.mozilla.org/en-US/docs/Web/Security/Securing_your_site/Turning_off_form_autocompletion
Example
<form method="post" action="/form" autocomplete="off">
[…]
the information you are seeing in your browser is stored in your browser try it from some other device it wont show up.