You have to file Form I-131 with the USCIS to apply for a re-entry permit, refugee travel document or advance parole travel document, to include parole into the US for humanitarian reasons.
Advance Parole is for a person having a pending Form I-485, Application to Adjust Status to Lawful Permanent Resident (green card holder), and who intend to travel before the I-485 application is approved. A Refugee Travel Document is for applicants who hold Refugee or Asylee status and who want to travel abroad and a re-entry permit is for green card holders who will be outside of the US for an extended period of time, generally a year or more.
If you are filing Form I-131, Application for travel document based on your pending or approved Form I-821, you have to mail the form to the USCIS Dallas Lockbox facility. Do not forget to attach a copy of the I-797, Notice of Action that shows that your application was accepted or approved. If you are applying to get your advance parole document renewed, the USCIS will accept and adjudicate Form I-131 filed up to 120 days before the date your current Advance Parole document expires.
You are required to complete biometrics at a USCIS Application Support Center (ASC). If you are applying for a Refugee Travel Document when you are abroad, you have to get the biometrics done at an overseas USCIS facility. All applicants aged between 14 and 79 years applying for a Refugee Travel Document or Re-entry Permit have to be fingerprinted as part of USCIS biometric service requirements. After you file this form, USCIS will review it and will notify you in writing of the time/location of your biometrics appointment. If you do not attend for biometrics, it might lead to a possible rejection of your application. If you are applying for a Re-entry Permit and/or Refugee Travel Documents and aged between 14 and 79, you should pay an additional $85 fee for biometrics.
The submission fee for advance parole or re-entry permit is $360 and for a Refugee Travel Document for an applicant aged 16 or older is $135. For a child below the age of 16 years, the fee is $105. For applicants aged between 14 and 79, a biometric fee of $85 is required for a Reentry Permit and a Refugee Travel Document, unless the applicant resides outside of the US at the time of filing the form. But note that a biometric fee is not needed for advance parole applicants.