If you are asking about your 2023 taxes, which were due April 15, 2024, you can't get an extension that long.
If you are asking about 2024 taxes, due April 15, 2025, you have three options.
1. File an electronic request for extension. You can't do this until February 2025.
2. File an extension by mail using form 4868. You must mail the form after January 1, 2025 and before April 15, 2025. If you are mailing from overseas, you should use a service with tracking.
3. You can get a 2 month automatic extension to June 15 if you are overseas, but you can't claim this electronically. To claim the 2 month overseas extension without using method 1 or 2, you have to file your return by mail and attach a written explanation. I would recommend method 1 or 2.
In all cases, if you expect to owe taxes, you should make a payment by April 15, to avoid late-payment penalties. If you expect to owe more than $1000, you should be making quarterly estimated payments all through the year, because if you owe more than $1000 when you file, you can be assessed an underpayment penalty even if you pay in full when you file.
