user88899: In the following article What Are Bitcoins? How Do Bitcoins Work?, it is mentioned that a blockchain is composed of three parts:

Identifying address
History
Private key header

Although, after taking a look at this question "Can someone explain how the Bitcoin Blockchain works?"
  it doesn't reflect what that article mentions. 
If those three parts are the actual parts of a blockchain, can someone provide a better explanation for each one? 

user30668: They are not. They might be provided to try to provide a better explanation, but I don't even think that this purpose is achieved. There are several sentences throughout the article that make no sense at all, like:

A bitcoin, at its core, is a very simple data ledger file called a 'blockchain'. A blockchain's file size is quite small, similar to the size of a long text message on your smartphone.

I would recommend you to look at the question you mentioned , that actually have two really good answers, and ignore the first article.

88899: <p>In the following article <a href="https://www.lifewire.com/what-are-bitcoins-2483146" rel="nofollow noreferrer">What Are Bitcoins? How Do Bitcoins Work?</a>, it is mentioned that a blockchain is composed of three parts:</p>

<ul>
<li>Identifying address</li>
<li>History</li>
<li>Private key header</li>
</ul>

<p>Although, after taking a look at this question "<a href="https://bitcoin.stackexchange.com/questions/12427/can-someone-explain-how-the-bitcoin-blockchain-works">Can someone explain how the Bitcoin Blockchain works?</a>"
  it doesn't reflect what that article mentions. </p>

<p>If those three parts are the actual parts of a blockchain, can someone provide a better explanation for each one? </p>
 30668: <p>They are not. They might be provided to try to provide a better explanation, but I don't even think that this purpose is achieved. There are several sentences throughout the article that make no sense at all, like:</p>

<blockquote>
  <p>A bitcoin, at its core, is a very simple data ledger file called a 'blockchain'. A blockchain's file size is quite small, similar to the size of a long text message on your smartphone.</p>
</blockquote>

<p>I would recommend you to look at the <a href="https://bitcoin.stackexchange.com/questions/12427/can-someone-explain-how-the-bitcoin-blockchain-works/42515#42515">question you mentioned</a> , that actually have two really good answers, and ignore the first article.</p>
