searchwp-4-supplemental-search-form-sample.php

<form role="search" method="get" class="search-form" 
      action="<?php echo site_url( 'search-results/' ); ?>">
    <label>
        <span class="screen-reader-text">
            <?php echo _x( 'Search for:', 'label' ) ?>
        </span>
        <input type="search" class="search-field"
            name="searchwp"
            placeholder="<?php echo esc_attr_x( 'Search...', 'placeholder' ) ?>"
            value="<?php echo isset( $_GET['searchwp'] ) ? esc_attr( $_GET['searchwp'] ) : '' ?>"
            title="<?php echo esc_attr_x( 'Search for:', 'label' ) ?>" />
    </label>
    <input type="submit" class="search-submit"
        value="<?php echo esc_attr_x( 'Search', 'submit button' ) ?>" />
</form>