IDOC help - income statement from an employer

As I am filling out the IDOC form, a lot of universities are asking for an income statement from an each working parent’s employer providing info about “current annual gross wages, bonuses, and benefits (automobile, housing and education allowances), along with taxes paid”

So, my questions are:

  1. Is there any kind of template for this letter?
  2. If I am applying for 2021, do I have submit documentation from both 2019 and 2020?
  3. And if one of my parents changed their job in September 2019, is the income statement from the former employer also required?

I am an international student, btw. Much thanks in advance!