No, filing an extension will not add "days of physical presence" in 2019. Your "days of presence" started when you obtained the H1B visa. As a result, you don't meet the Substantial Presence Test in 2019 and will need to file as a nonresident (Form 1040-NR) for 2019.
When you meet the Substantial Presence Test in 2020, you'll qualify to be treated as a resident on the first day of 2020 you were present in the United States according to IRS Publication 519 at this link. Once you qualify to file Form 1040 as a U.S. resident for tax purposes, you use the same deductions, including the standard deduction for your filing status.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
