What is an in forma pauperis?

A motion for leave to proceed in forma pauperis (Latin: in the form of a pauper) is notice to the court that the petitioner has limited funds and is asking the justices to use their discretion to reduce the financial demands on the party by waiving docketing fees, requiring fewer copies of briefs, etc.

In other Words, it is a petition filed by a poor person to proceed to court without any extra court fees such as filing fees, etc.