how to insert an edit point to a curve?
 

please let me know how!

thanks

Select curve. Goto "edit curve" and "add points tool". This will and an extra point at the end of the curve. (You can pointsnap this to another curve by using "v"-button).

is there a way to insert a point in the middle of the curve? at an exact location where i want it?

Yes... goto curve point mode. Click/drag the extra point you want to add. Then select "edit curve" and "insert knot".

thanks master kuhl!

BTW... its a good idea to rebuild curve after inserting a knot i think... Otherwise you can get some odd behaevior.