Hello @lhpereira

Unfortunately you cannot do that right now but you can if you create a new page template.

This will help you https://premium.wpmudev.org/blog/creating-custom-page-templates-in-wordpress/?utm_expid=3606929-101._J2UGKNuQ6e7Of8gblmOTA.0&utm_referrer=https%3A%2F%2Fwww.google.com.mx%2F

You can use the existing Full-width page template and add a sidebar position to it, which you can then add widgets to.

Let me know if you have any questions.