Locking a file or folder in Mac book

Hi,

Following tips could be answer your question.

In the Finder on your Mac, open a window, then Control-click the item you want to encrypt in the sidebar. Choose Encrypt [item name] from the shortcut menu. Create a password for the disk and click Encrypt Disk. Important: Be sure to record and keep this password in a safe place.

Protect a document with a password

1. Go to File > Info > Protect Document > Encrypt with Password.
2. Type a password, then type it again to confirm it.
3. Save the file to make sure the password takes effect.

I'm trying to encrypt a folder. Using the info above, I can't find just "info" under "file" & can't find "protect document" nor "encrypt with password. In the past, I've encrypted folders. How do I do that now??