Hello !
If you are filing an extension to exclude your foreign earned income, you need to file a Form 2350 Application for Extension of Time To File U.S. Income Tax Return. This is a different extension than the normal extension Form 4686, which TurboTax supports. As TurboTax does not support the form, to file this extension, you
will need to download the form from IRS website:
https://www.irs.gov/uac/about-form-2350
For more information , see Extension Form 2350
If you are filing an extension not to exclude a foreign income, then you would simply follow these steps :
1. After sign into your account, select Take
me to my return
2. At the right upper corner, in the
search box , type in extend and Enter
3. Select the 1st choice on the search
results - Jump to extend / and follow prompts.
4. On screen, Add or edit your info, leave the address portion blank
You cannot e-file, but print out the Form 4686 and hand-write your foreign address in the appropriate space.
I hope the information helps !!