My in-laws lived with us for more than 6 months last year and we need to declare them as dependent. From IRS website, it seems that all we need to do is fill out a W-7 form and notorized Passports, attached them with tax return documents and send these material to W-7 special unit mail box. My questions are:

1) besides the mail to location that specified in W-7, should the tax documents (1040) be sent to any other locations?

should be same address as where you are mailing Form W7.

2) On 1040, we should write their information under dependent section, right?

that is correct.

3) Is there any thing else missing?

you may check this link: http://www.huaren.us/dispbbs.asp?boardid=336&id=185901

If anybody knows, please help.