Hello @akadibaba,
1. The file is wp-content/themes/woopress/woosearchform.php.
2. The file is wp-content/themes/woopress/framework/theme-functions.php (line 826).
3. The file for header type 17 is wp-content/themes/woopress/headers/header-structure-6.php.
4. Fixed header code is written in the file wp-content/themes/woopress/header.php.
Regards, Eva Kemp.
