@adnanibnekhair , as I understand from your post:
1. You entered USA on F-1 in 2015. Thus your exempt status ran from 2015 through 12/31/2019
2. Your status was adjusted on 01/01/2019 ( please provide exact date )
This would mean that from the date of adjustment of status you would start counting days towards Substantial Presence Test. From the date you pass the SPT you are a Resident Alien for tax purposes ( filing form 1040 and taxed on world income ) while prior to that you are a Non-Resident Alien for tax purposes ( filing form 1040-NR and reporting ONLY US sourced income.
If your world income for the first part of the year was the same as US sourced income, then you can request to be treated as a resident for the whole calendar year. Just file a form 1040 covering world income for the whole year and include a note to the IRS requesting to be treated as a Resident for Tax purposes for the whole year. This of course would mean that (a) you can use TurboTax for preparation of the taxes and (b) you have to file by mail.
Does this answer your query or do you need more help ?
