i was not able to add library from sketch
You're not supposed to copy it from sketch. Use Windows Explorer.
the .rar was not appearing from there
Where did I say anything about .rar? I didn't.
id copied the folder u8glip.h and u8glip.cpp
Those aren't folders, those are files.
to marlin folder where is the whole libraries but didnt work also
probably i think because thats the 1.5.x folder and im using 1.6.8
No, it didn't work because the include syntax is wrong for using those files in the sketch folder. You would need to change the include(s) to:
As I said before, that's an old version of Marlin but you seem set on using it so whatever.
Have you installed the U8Glib library? If you have Marlin configured (in configuration.h) for one of the LCD control panels it will want the U8Glib library. Check https://github.com/olikraus/U8glib_Arduino for further information.
Marlin includes the U8glib library(which I have instructed OP how to install). The reason for this is they want to make sure that the version of the library they tested is used instead of a different version that may not be compatible.