Hello Mairena,
Currently, WooCommerce provides that checkbox only at the checkout. To add it on the login page, there is major customization required.
Unfortunately this level of customization is beyond our scope of support as it’s more work than a small customization. While we’d love to be able to support every customization request, we simply don’t have the time to do so. We recommend that you should enlist the help of a web developer if you need that functionality, potentially from one of the below resources:
https://codeable.io
Home
http://www.studio.envato.com
Hope that helps.