WP is used in front of the grades for pipe fittings after the production standard. Like ASTM A403 WP304L. TP is used in front of the grades for pipes (not fittings) after the production standard. Like ASTM A312 TP304L.
make sure you are an op or have permission for the command and type this into the text box (bring up by pressing T) : /tp <yourname> <theirname> if you want to tp to them. if you want to tp them to you you can do /tp <theirname> <yourname>