3. How to edit the logo image
You can edit the column and the Site Logo styles:
To set the logo size, visit the Style section:
You can edit the Logo image, Site title and Tagline in Customize > Site identity:
You can check this guide for more details: Vamtam Elementor Themes: How to edit the Logo image, Site Title and Tagline?
Editing the header for mobile resolution
Switch between Desktop, Mobile or Tablet views by clicking on the corresponding icons on the bottom of the panel and edit the content dedicated to the corresponding resolution:
You can also check this instruction: https://elementor.com/help/mobile-editing/