Where can I find a user guide for MacBook Pro (13 Inch, Late 2012) OS X Yosemite, Version 10.10.5?

Official product manuals are here: https://support.apple.com/manuals. For your model, I can find a Quick Start Guide, but not a more comprehensive User Guide like those available for earlier models.

OS X 10.10 Yosemite is no longer supported. Your computer can run macOS Catalina (10.15), a free upgrade that will give you the latest features and compatibility with newer services. Most importantly, keeping current with software updates is one of the best ways to protect your computer from malicious software.