You must file this form if you are filing Form I-485, Application to Register Permanent Residence or Adjust Status, and you are subject to the public charge ground of inadmissibility.
In general, each applicant who submits Form I-485 must submit his or her own Form I-944 if the applicant is subject to the public charge ground of inadmissibility
https://www.uscis.gov/system/files_force/files/form/i-944instr-pc.pdf?download=1