Hi.
There are a lot of things here that need to be corrected, and I'm not sure where to start.
Try starting with this: My dream job is to work in the Information Technology field as a software programmer. Some of the reasons I've chosen this career are ...
Now, before you try to write them into your essay, list them briefly. A shortage of IT workers, what else, what else.
Then start a new paragraph and write a bit more detail about each of these. The sentence about the Web site made almost no sense, so work on that one.
Now, as for the final paragraph, you start with "my" but switch to "one." Pick one person (I/me/my or a person/one/he/she) and stick with it. You need an article before computer, or you need to make it plural. Since you use "they" afterwards you should probably make it plural.
So go back and try it again, taking things more slowly.