How to edit my account page, where to edit the content inside, where can I see the message if the customer has registered, where can I see her order if the customer has placed an order?
1. Sorry, but the “Page title” cannot be edited via Elementor so please explain what exactly you want to change in the page title and I will do my best to help you.
2. The sidebar can be edited via Appearance -> Widgets -> Main Widget Area.