My dear wife got a new Mac computer and when she set it up, she didn’t write down her ID and password. Now, everytime she wants to install a progrem or do something, she is asked for the Password but we cannot put it because it is forgotten. is it stored anyplace in the computer? What if anything can we do? Any help will be extremely appeciated.
Shut down the Mac. Start it back up and hold down Command-S. Wait for it to boot up. This will take a couple of minutes. Once it’s up, you will be in single-user mode. At this point you can run the command “passwd” from the command line. This will allow you to specify a new password without needing to know the old one.
Note that this is from memory from when I had forgotten my old password on a system, and things might have changed since then.
Thanks… I will tell her to try that method. Looks good! 
This will not work on anything other than a really ancient version of OS X.
Tell me what version you have, and I will tell you how to reset (not recover) the password.