A small 71.5 KB PDF with the very short name 16f, indexed as a schematic. The name is too terse to tell what device, series or component it covers, so the contents need to be checked directly. At this size it is most likely a brief component datasheet or a single-page diagram rather than a full board schematic. Open it in any PDF reader, identify the part or circuit it documents, and compare it with the markings on the actual component before using any pinout or rating.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.