HTML tags in a block body are not rendred
It's rendering the block's content a plain text, not HTML, because you aren't setting the body field's format property when creating the BlockContent entity. 

$blockContent = \Drupal\block_content\Entity\BlockContent::create([ 'type' =&gt; 'basic', 'info' =&gt; 'Why choose us?' ]);
$blockContent-&gt;body-&gt;value = '&lt;p&gt;&lt;i class="fa fa-drupal"&gt;&amp;nbsp;&lt;/i&gt;&lt;/p&gt;
                              &lt;p&gt;Lorem Ipsum is simply dummy text of the printing and typesetting industry.&lt;/p&gt;';
$blockContent-&gt;body-&gt;format = 'full_html';
$blockContent-&gt;save();