You must file 2016 and 2017 Forms 5329 to report and pay the excess contribution penalties associated with the excess contributions. On the 2016 Form 5329 you'll have a penalty of 6% of the amount that you contributed for 2016 and on the 2017 Form 5329 you'll have a penalty on 6% of the sum of the contributions made for 2016 and 2017.
You'll also have 2018 From 5329 reporting the same excess (2016 excess contribution plus 2017 excess contribution) as on the 2017 Form 5329 and pay the same amount of excess contribution penalty with your 2018 tax return.
The distribution made in 2019 will be reportable on your 2019 tax return.
These excess contributions were correctable in 2019 by a regular distribution of exactly the amount of the excess, with no adjustment for earning. The distribution of the actual excesses is not taxable because it is a distribution attributable to your contribution basis, but the earnings distributed will be taxable and potentially subject to early-distribution penalty if you have no other Roth IRA contribution or conversion basis to apply to the amount distributed in excess of the amount of the excess contributions.
