Software Update
a friend gave me her MacBook Pro and I want to update the software and I would like to know how to do that.
MacBook Pro 13″, macOS 10.12
Is your signature indicative of what you have?
10.13 is an upgrade, not an update to 10.12.
You posted to the 10.13 forum.
First you need to identify the computer you have. Then read this FAQ*: on what you can upgrade to:
http://www.macmaps.com/docs/DOC-13695/
*Links to my pages may give me compensation