As a F-1 visa holder, you are
considered as "exempt" meaning not counting days for five years
starting from the date of your first arrival in the United States. After
the five years period, you will start counting days by using the Substantial Presence Test to see if you qualify to be
treated as a US resident for tax purposes.
In your situation, you are
considered as a nonresident from 2015-2019 filing a Form 1040-NR. Starting
from 01/01/2020, you will start counting your days. If you meet the
Substantial Presence Test in 2020, you will be considered a US resident for tax
purposes and file a Form 1040 for your tax year of 2020.
For examples, see :https://www.irs.gov/individuals/international-taxpayers/alien-residency-examples
Since you have filed your Form 1040, you will need to do an amendment. Here are the steps:
-If you are considered as a nonresident, as TurboTax
does not support the NR form, you are recommended to use our affiliated
partner, Sprintax to complete your 1040-NR filing.
1. Download the Form 1040-X from IRS website ( see
below). On the front page of Form 1040-X, enter your name,
current address,
and social security number (SSN) or IRS individual taxpayer identification
number (ITIN)
2. Do not enter any other information on page 1.
3. Do not complete Parts I or II on page 2 of Form
1040X.
4. Enter in Part III the reason why you are
filing Form 1040X.
5. Complete a new or corrected form 1040-NR by using
Sprintax, see above.
6. Across the top of the 1040-NR, write “Amended”
7. Attach the new or
corrected return (Form 1040, Form 1040NR, etc. to the back of Form 1040X
