When can I file a 1040 form for 2021

[NCperson]

late January 

[NCperson]

The IRS is expected to open up the filing window in late January 

[VolvoGirl]

The IRS has not updated all the forms yet. See
https://ttlc.intuit.com/community/forms/help/irs-forms-availability-table-for-turbotax-individual-pe...

Even when the IRS finalizes the Forms you need and Even if Turbo Tax lets you submit your return they will just hold all the returns until the IRS opens filing on Jan 27, 2021 or later. So there is no hurry. And a lot of people who file early find out they have to amend later like when they get their actual W2 and 1099 forms. Or they get more forms than they were expecting.

And You should wait because you might get a late W2 or 1099 in the mail. They have until Jan 31 to send you the tax forms. Or they may send you a corrected W2 or 1099 even later.