widget next header

Yes, but you will need to be more specific in your request for help.

A widget can be placed anywhere where you ‘tell the theme it can be displayed there’:
https://codex.ww.wp.xz.cn/Widgetizing_Themes

In other words, the *reason* themes display widgets in particular areas is bc there is code and functions in the template file that accommodate this.

Here is an example of creating a widget, and adding this space to your theme:
https://www.wpbeginner.com/wp-themes/how-to-add-a-wordpress-widget-to-your-website-header/