Greetings to my fellow steemians
It's with great pleasure I am here to write and to accomplish my achievement 4 task. I would like to say a big thank you to @cryptokannon, and @josepha, for this wonderful lesson in this achievement task and for your constant support.

What is markdown?
Markdown: is a lightweight markup language for creating formatted text using a plain-text editor. John Gruber and Aaron Swartz created Markdown in 2004 as a markup language that is appealing to human readers in its source code form. Markdown is widely used in blogging, instant messaging, online forums, collaborative software, documentation pages, and readme files.
source

Types of markdown

Many of the most popular Markdown applications use one of the following lightweight markup languages:

1. CommonMark.
2. GitHub Flavored Markdown (GFM)
3. Markdown Extra.
4. MultiMarkdown.
5. R Markdown.

here
It's necessary to make your post look so neat and attractive on steemit to make reading and accessing some posts very easy for someone to read.
The example shown below is the following markdowns which should be used constantly to make your post look nice, attractive, and readable.

MARKDOWN FOR HEADING

TYPES OF COMPUTERS

TYPES OF COMPUTERS

TYPES OF COMPUTERS

TYPES OF COMPUTERS

TYPES OF COMPUTERS

The above is created by writing # tag and then giving a space then typing the heading;

Headline 1

Headline 2

Headline 3

Headline 4

Headline 5

This indicates that; the more the # sign the smaller the size becomes.

MARKDOWNS FOR CENTER ALIGN, RIGHT ALIGN, AND LEFT ALIGN TEXT AND IMAGES

We will consider the text " I am here to accomplish my achievement 4 task".

TEXT RIGHT I am here to accomplish my achievement 4 task.

TEXT LEFT I am here to accomplish my achievement 4 task.

CENTER TEXT
I am here to accomplish my achievement 4 task

IMAGE ALIGNMENT

source

MARKDOWNS IN CREATING TABLE MERITS OF INTERNET DEMERITS OF INTERNET
For ResearchSpamming For Making online money theft, and hacking Easy communicationsornographic and violent images

This output can be done by creating the table below:
This is a table showing the serial numbers,names and phone numbers,
Table:

S/N.	name	phone number
0001	agency	08067545038
0002	Monday	08094503738
0003	Sunday	08086658458

MARKDOWN FOR BLOCKQUOTES

e.g. Imagination is more important than knowledge. Writing this in blockquote we get:

Imagination is more important than knowledge.
Melick Joshua

MARKDOWN FOR ADDING VIDEOS OR GIFS

here

Conclusion

I have learned a lot from this achievement and I would make sure I do apply the constant Markdowns in every of my post to make post look so nice and attractive. Thank you very much for this great lesson taught.
Thank you all for reading.

Specially I want to thank the people who
operate this great community. The
admins & moderators are very helpful for
newcomers. Special thanks to @cryptokannon, @sm-shagor, @bright-obias, @besticofinder, and @ngoenyi I've started posting here by following your introduction.