Since you are a US resident for tax purposes, by receiving a Form 1042- S with the code 16, you will treat it as receiving a scholarship or fellowship to offset your qualified education expenses if there are any.
- At the right upper corner, in the search box, type in "1098t" and "Enter"
- Select Jump to 1098t in the top of the results box
When you enter your form 1098-T for education expenses you will be asked about other scholarships/grants not reported on your 1098-T. There you can enter your 1042 amount. You also be asked about the education expenses paid with the scholarship/grant or out of pocket.
Further, if your form 1042 shows withholding you can enter that under the "Deductions & Credits" tab.
- Scroll down to Estimates and Other Taxes Paid
- Click on Other Income Taxes
Here is an excellent link with a previous answer from @KarenJ2.