Hello. I have a Chromebook device running Chrome OS and I don't know how to update it. I need to do it as many of the functions of this device are failing me. I will appreciate any help you can give me.

Updates are delivered automaically, so you don't need to worry about them.

Yes, I know it should update automatically, in fact it did in the beginning but not anymore, I don't know why. For that reason I need to know how I can update it. Many of its functions are failing and others have stopped working due to outdated operating system.

Sounds like it's aged out on updates.
This should help: https://support.google.com/chrome/a/.../6220366?hl=en

Though Chrome OS devices will auto update you can also check for updates manually.
https://www.youtube.com/watch?v=Jbqr_YnGUdQ