Are you looking for where to file 1042 online?
IRS approved Tax1099.com allows you to create and submit the 1042.
You will then be able to download and print the 1042 to mail into the IRS.
Note: The IRS does not accept e-file of the 1042 form.
IRS Form 1042 is used to report a foreign person's income if it is sourced in the
U.S. and is subject to withholding.
Example use: Payers use this form to report payments to foreign persons.
When would you need to file a 1042?
Every withholding agent or intermediary who receives, controls, has custody of, disposes of, or pays a withholdable payment (to which chapter 4 withholding applies) or an amount subject to withholding, must file an annual return for the preceding calendar year on Form 1042.
Any PTP or nominee making a distribution of ECI under section 1446, or any entity required to report a distribution on Form 1042-S that is subject to withholding under section 1445, must file Form 1042.