TFormVector doesn't take position into account, while TFormPoint does.
TFormNormal is the same as TFormVector except it normalizes the vector, so it always has a length of 1 unit.
An example would be, you want to know where a vertex in a mesh is in your world/game, so you use:
TFormPoint VertexX,VertexY,VertexZ,mymesh,0
You might also want to know which direction the vertex's normal is pointing in the world/game, so you use:
TFormVector VertexNX,VertexNY,VertexNZ,mymesh,0
(You could also have used TFormNormal for that)
So TFormPoint is for finding out stuff about a location, while TFormVector is for finding out stuff about a direction.
TFormNormal is the same as TFormVector except it normalizes the vector, so it always has a length of 1 unit.
An example would be, you want to know where a vertex in a mesh is in your world/game, so you use:
TFormPoint VertexX,VertexY,VertexZ,mymesh,0
You might also want to know which direction the vertex's normal is pointing in the world/game, so you use:
TFormVector VertexNX,VertexNY,VertexNZ,mymesh,0
(You could also have used TFormNormal for that)
So TFormPoint is for finding out stuff about a location, while TFormVector is for finding out stuff about a direction.