I can’t find the Shared permission on a workgroup computer formatted with NTFS. But I logged in as the administrator. The OS is XP. Only Local/Network sharing and security that is present, and a can I password a shared folder on a work group. All the clients are XP

There are lot of security not available in a workgroup that you can get in a domain environment. Unlike in a domain where you can select users and the different access levels they have to a share, you can only set thesame access level in a workgroup.
This can be made by setting a password access to the share. To do this, simply turn-off the guest account, make sure the account you are logged on as is password protected.
Alternatively, if the share resides under your profile(Documents And Settings\%username%), simply making your files private enables password authentication on access over the network.