What is "it" that is asking for your 2019 1099-G?
Form 1099-G is used for a lot of different kinds of government payments. Are you looking for a 1099-G for a state tax refund, for unemployment benefits, or for something else?
The 1099-G comes from whatever government agency made the payments. You will have to check with them to find out the availability of the 2019 1099-G, and how to get a copy.
A 2019 Wage & Income Transcript from the IRS will list the information from the 1099-G that was issued to you, but not in the format of the actual 1099-G form. Go to the following link on the IRS web site to get a transcript. You want a Wage & Income Transcript, not a Tax Return Transcript.
Get Transcript