In case you want to change the default word “Search” in the Search Button, into something different, this snippet will allow to change it.

Changing the search string in WordPress search form

/*/
/* Change Search Button Text
/*/

add_filter('get_search_form', 'my_search_form');
 
function my_search_form($text) {
     $text = str_replace('value="Search"', 'value="ok"', $text); //set as value the text you want
     return $text;
}

Awesome thank you for sharing ! Could you help me to replace `placeholder="Search …" with custom text

<input type="search" class="search-field" placeholder="Search …" value="" name="s">

So if you want to replace placeholder in search field here is code

/**
 * Replace the search form placeholder text.
 *
 * @param string $form The HTML markup of the search form.
 * @return string
 */
function my_custom_search_placeholder( $form ) {
    // Replace the default placeholder
    $form = str_replace(
        esc_attr_x( 'Search …', 'placeholder' ),
        esc_attr__( 'Find on my blog …', 'text-domain' ),
        $form
    );
    return $form;
}
add_filter( 'get_search_form', 'my_custom_search_placeholder' );