If you have applied for an adjustment of status or a green card or have US immigrant processes pending or have applied for certain immigration benefits and need to leave the US for some reason, you will need to have an Advance Parole travel document in place before you travel to ensure that you can re-enter the US. If you have a green card but may be out of the US for an extended period of time, you may also need an Advance Parole travel document. The Advance Parole travel document allows you to re-enter the US and also is a declaration that you do not intend to abandon your immigration petition or status. If you travel without this document and you need it, you may not be able to get back into the US and you may find that you lose your status in the US. Even if you just cross the border into Canada or Mexico or the Bahamas, you may have to remain outside the US and apply to re-enter through a consulate, so the Advance Parole travel document is very important.
It is important to apply for and receive your Advance Parole travel document before you leave the US. You are eligible to apply for advance parole if you are in the US and have filed form I-485 (adjustment of status). You can even file for advance parole at the same time that you file form I-485.
You can also file for advance parole if you have asylum or refugee status and want to travel to Canada to apply for a US visa or want to travel outside of the US for business reasons or urgent personal reasons. You will also want to file for advance parole if you have an immigration status (such as Temporary Protected Status) that allows you to return to the US after a short visit. If you are outside the US, you may apply for advance parole if you need to visit the US urgently and temporarily for an urgent humanitarian cause. However, this is not a typical application and such applications are considered on a case-by-case basis. Usually, it is vital to apply for an Advance Parole travel document before you leave the US.
If you believe that you need an Advance Parole travel document, try to apply for one as far in advance of your travel as possible, to ensure you receive your document before you must travel. To file for the Advance Parole travel document, you will need to file USCIS Form I-131 (Application For Travel Document) along with the current filing fee for the form. You can find the latest version of the form as well as all relevant documents on the USCIS website. With your application, you will need to also include two identical photos of yourself as well a copy of a piece of identification. Follow the USCIS directions precisely about these additional requirements.