Thanks for asking.
- If you want to turn off site search then it can b done from X > Theme Options > Header > Search.
- You can change the search lightbox text from /wp-content/themes/x/framework/legacy/cranium/headers/functions/navbar.php and make the changes in following code:
<label for="s" class="cfc-h-tx tt-upper"><?php _e( 'Type and Press “enter” to Search', '__x__' ); ?></label>
and /wp-content/themes/x/framework/views/global/_content-none.php to make changes into 404 search page text.
Before making any changes I suggest you to install child theme and copy the files from above shared path into child theme in the same order by creating the necessary child folders.
You can use following resources to download and setup child theme.
Download Child theme from following source: https://theme.co/apex/child-themes
Please take a look at following article to setup child theme:
To learn more about translation, please take a look at following article.