In Documents, you can play or view files of various formats (extensions). Here is the full list of them:

• Audio player: .aac, .aif, .aifc, .aiff, .au, .l16, .m3u, .m4a, .m4b, .m4p, .mp3, .pcm, .wav, .flac
• Video player: .3gp, .l16, .m3u, .m4v, .mm, .mov, .mp4, .scm, .avi, .mkv, .flv
• PDF viewer & editor: .pdf
• Image viewer: .png, .jpg, .jpeg, .bmp, .gif, .ico, .tiff, .xbm, .tif, .tga, .heif, .heic, .dng, .cr2
• Unarchiver: .zip, .rar
• eBook reader: .epub, .fb2
• Microsoft Office viewer: .doc, .docx, .xls, .xlsx, .ppt, .pptx
• iWork viewer: .pages, .numbers, .keynote, .key
• Code viewer & editor: .php, .asp, .java, .sh, .css, .sql, .phtml, .pl, .pm, .py, .rb, .c, .js, .cl, .scm, .ss, .lisp, .cc, .cs, .cpp, .cxx, .m, .mm, .h, .swift
• Text viewer & editor: .txt, .rtf, .rtfd, .log, .tex, .md, .odt, .pdb, .guide
• Web viewer: .htm, .html, .webarchive