The 2021 form 1040 will look very much like the 2020 form. There are only minor changes to the two-page form, based on a draft of the form.
Schedules 1,2 and 3 are much longer because they will list specifics for other types of income, adjustments, credits, etc. For example, the 2020 Schedule 1 asked for other income as a general category on line 8. The draft 2021 Schedule 1 separates line 8 into 17 income types, such as cancellation of debt and stock options. The formerly one-page Schedules 1,2 and 3 will now each be two pages in length.