FillAnyPDF is a form-filling service. It helps users take information from disparate sources and collocate them into a single PDF document. Text from Microsoft Word, for example, can be simply uploaded into the FillAnyPDF form. Also, multiple users can collaborate on and sign a single document. The FillAnyPDF API exposes the platformâ€™s entire functionality. It is a RESTful API that returns XML-encoded data.