How to set up header for mobile devices
Go to WordPress admin panel > On dashboard sidebar navigate to Templates > Saved Templates > Edit with Elementor your Header template
By Elementor page builder from Responsive mode select mobile device
Edit the Columns width of your header > Edit Column > Layout > Layout – Column width
For example if you have two columns, one for logo and one for main menu. Set the first one with width 80% and the second one wit width 20%.