Works with P2 theme?

I saw the solution below, how do I apply it to my code post-form.php?

ob_start();

then after your form add:
$form = ob_get_clean();
echo do_shortcode(‘[IN_LIMIT] ‘ .$form. ‘ [/IN_LIMIT]’);

My code:

<?php
/**
 * Front-end post form.
 *
 * @package P2
 */
?>
<script type="text/javascript">
/* <![CDATA[ */
	jQuery(document).ready(function($) {
		$('#post_format').val($('#post-types a.selected').attr('id'));
		$('#post-types a').click(function(e) {
			$('.post-input').hide();
			$('#post-types a').removeClass('selected');
			$(this).addClass('selected');
			if ($(this).attr('id') == 'post') {
				$('#posttitle').val("<?php echo esc_js( __('Post Title', 'p2') ); ?>");
			} else {
				$('#posttitle').val('');
			}
			$('#postbox-type-' + $(this).attr('id')).show();
			$('#post_format').val($(this).attr('id'));
			return false;
		});
	});
/* ]]> */
</script>

<?php $post_format = isset( $_GET['p'] ) ? $_GET['p'] : 'status'; ?>
<div id="postbox">

	<div class="postboxcontent">
<ul id="post-types">
	<b><a id="post" class="post-format-button<?php if ( 'post' == $post_format || 'standard' == $post_format ) : ?> selected<?php endif; ?>" href="<?php echo site_url( '?p=post' ); ?>" title="<?php esc_attr_e( 'Currently Viewing all Network Posts', 'p2' ); ?>"><i class="fa fa-eye"></i> <?php _e( 'Currently Viewing all Network Posts', 'p2' ); ?></a></b>
		</ul>
		<div class="avatar">
			<?php echo get_avatar( get_current_user_id(), 240 ); ?>
		</div>

		<div class="inputarea">
ob_start();
			<form id="new_post" name="new_post" method="post" action="<?php echo site_url(); ?>/">
				<?php if ( 'status' == $post_format || empty( $post_format ) ) : ?>
				<label for="posttext" id="post-prompt">
					<center><?php p2_user_prompt(); ?><br><br><hr><img src="https://caldr.com/wp-content/uploads/2015/12/click-to-post.png"></center>
				</label>
				<?php endif; ?>
				<div class="inputs">
<?php if ( current_user_can( 'upload_files' ) ): ?>
				<div id="media-buttons" class="hide-if-no-js">
					<br><?php p2_media_buttons(); ?>
				</div>
				<?php endif; ?>

<input type="text" name="posttitle" id="posttitle" value="Post Title"
						onfocus="this.value=(this.value=='<?php echo esc_js( __( 'Post Title', 'p2' ) ); ?>') ? '' : this.value;"
						onblur="this.value=(this.value=='') ? '<?php echo esc_js( __( 'Post Title', 'p2' ) ); ?>' : this.value;" />

					<textarea class="expand70-200" name="posttext" id="posttext" rows="4" cols="60"></textarea>

					<label class="post-error" for="posttext" id="posttext_error"></label>
					<div class="postrow">
						<input id="tags" name="tags" type="text" autocomplete="off"
							value="<?php esc_attr_e( 'Tag it', 'p2' ); ?>"
							onfocus="this.value=(this.value=='<?php echo esc_js( __( 'Tag it', 'p2' ) ); ?>') ? '' : this.value;"
							onblur="this.value=(this.value=='') ? '<?php echo esc_js( __( 'Tag it', 'p2' ) ); ?>' : this.value;" />
						<input id="submit" type="submit" value="<?php esc_attr_e( 'Post it', 'p2' ); ?>" />
					</div>
					<input type="hidden" name="post_format" id="post_format" value="<?php echo esc_attr( $post_format ); ?>" />
					<span class="progress spinner-post-new" id="ajaxActivity"></span>

					<?php do_action( 'p2_post_form' ); ?>

					<input type="hidden" name="action" value="post" />
					<?php wp_nonce_field( 'new-post' ); ?>
				</div>*Html Allowed. Articles should be 100% original, no plr.<br>Your post is autoshared to 47,000 (and Growing) subscribers and followers in our network!
			</form>
$form = ob_get_clean();
echo do_shortcode('[IN_LIMIT] ' .$form. ' [/IN_LIMIT]');

		</div>

		<div class="clear"></div>

		<div class="postbox-sidebar">
			<?php dynamic_sidebar( 'beneath-post-box' ); ?>
		</div>

	</div><!--/.postboxcontent -->

</div> <!-- // postbox -->

I saw the solution below, how do I apply it to my code post-form.php, view here https://pastebin.com/jujv51uM

ob_start();

then after your form add:
$form = ob_get_clean();
echo do_shortcode('[IN_LIMIT] ' .$form. ' [/IN_LIMIT]');