Fucking Taxes, how do they work?

I absolutely have no idea what I'm talking about, so I'm going to try different approaches to get the message across:

Approach 1: What is the normal course of action an individual would have to go through to file a tax return, from the VERY start to end?

My guess:
1/ Tax season rolls around
2/ Taxpayer gets reminded to do the filing. How? Choose one that applies:
[INDENT]a/ Employer reminds employee to file[/INDENT]
[INDENT]b/ DIY[/INDENT]
[INDENT]c/ IRS reminds taxpayer by sending something via the postal service[/INDENT]
3/ Taxpayer prepares the return: Choosing a form, filing it, sending it; or have an agent do it all
4/ ???
5/ Taxpayer reaps profits

Approach 2:
1/ There was a change in taxing legislation late last year, certain individuals with certain criteria are affected and have to wait until mid-late February to file their returns.
2/ I've heard from my father that the IRS sends him a notice/form/whatever annually which sets off his tax filing duty. However, this year, he hasn't received anything up until now, which, according to him, is strange.
Question: Is the lack of notice from the IRS an indication of my father being affected by the legislative change? or
Has e-filing been made universally mandatory and, thus, no such physical package is going to get sent?

Approach 3: pineapple taxes.

I'm not sure how it applies to Vietnamese (assuming you are, infact, living in Vietnam atm), but last year I was in university in Canada, and I had to wait until late February to get my tax return done. I had to wait on a form from the university so I could claim my tuition.

In the Netherlands:

- From January 1st ~ March 31st, you download the new tax tool (windows) from the government site.

- You fill in the data and numbers from previous year, send to you by your employer (income), bank (mortgage), etc

- You double check everything

- In the end you see how much tax you need to pay for the next year, spread out per-month.

- You click "send" and data is transferred via a secure connection

- After a few weeks, you get a paper letter with the official numbers, on how much you have to pay (this will be automatically deducted from your income, this saves bureaucracy), and how much you can cash back from the government (also automatically) every month.

- Done

Really easy!