如何将fa-fa图标插入搜索框

Question

enter image description here我需要一些有关搜索表单图标的帮助。

<div class="top">
        <div class="large">
          <div class="b1">
            <div class="label"><?php _e('What are you looking for?', 'veronika'); ?></div>
            <div class="box">
              <?php if (osc_get_preference('item_ajax', 'veronika_theme') == 1) { ?>
                <div id="item-picker">
                  <input type="text" name="sPattern" class="pattern" placeholder="<?php _e('Samsung S7 Edge...', 'veronika'); ?>" value="<?php echo Params::getParam('sPattern'); ?>" autocomplete="off"/>