There are three largely overlapping collections in papyri.info, the Duke Databank of Documentary Papyri (DDbDP), the Heidelberger Gesamtverzeichnis (HGV), and the Advanced Papyrological Information System (APIS). You can browse their collections by the print publication in which the relevant edition was published. For example, papyri from the series The Oxyrhynchus Papyri are listed under papyri.info/ddbdp/p.oxy.
The document search page has detailed information on the types of searches you can do on the right side of the page where search results appear.
Each document page has some combination of: data (from HGV), catalog data (from APIS), a transcription (from DDbDP), translation(s) (from HGV or APIS), and images (from APIS)
From any document page, you can click the "open in editor" link and you will be given the option to edit any aspect of the data (apart from the images). Changes you make and submit will go to an editorial board responsible for approving them and if accepted, your updates will be published, with attribution, on the papyri.info site.