When may I begin filling

[DoninGA]

A 2020 tax return cannot be filed until after January 1, 2021.  The IRS does not start accepting any type of tax return for processing until late January.

Make sure that you have received every W-2 and/or Form 1099 before filing the tax return.

Employers are required to provide a W-2 to no later than January 31.  Most financial institutions will provide a Form 1099 by the end of January or early February.

It is advisable that you wait until at least mid-February to file your tax return to avoid any issues that occur each year with tax returns filed in January.

[Opus 17]

Turbotax will open e-filing to stockpile returns on January 7.  However, the IRS has not announced yet when they will open e-filing, and early returns just sit in the data warehouse until the IRS opens.

Moreover, you are not legally allowed to file until you have all your required documents (W-2s, 1099s, etc,).  And not all part of the Turbotax program will be functional on January 7.  Depending on how long it takes the IRS to approve new forms and changes to the tax laws, some part of the program may not be ready until mid-February.  We can't know when it will be possible for you to file, based on your tax situation. 

https://ttlc.intuit.com/community/articles/community-news-announcements/tax-year-2020-upcoming-dates...

[Critter-3]

Also early filed returns have a higher chance of being audited or stopped for ID verification.  If your return will have EIC and/ or the Additional Child Tax credit on it then those returns will be held by the IRS until mid February before they start processing ... so be wise ... do not be in a big hurry to file.

Also, if you do file incorrectly you will need to amend the return once the original return has fully processed and that can take 4 - 6 months to process ... so filing an incomplete return early is not doing yourself any benefit.