Did you read through the information in full? Sounds like you didn't.But it says sponsors applying in 2021...
It's for expression of interest in 2020. Because invitations will be sent so late in the year, people won't submit their applications until 2021.
See the note:
Note: Because the program has opened later than usual this year, sponsors will be invited to apply near the end of the year so we expect to get applications in early 2021 (likely January and February). Because of this, we’ll assess sponsors on their income for tax years 2020, 2019 and 2018.