W-8 EXP Form is a
Certificate of Foreign Government or Other Foreign Organization for United Sates Tax Withholding.
For use by foreign governments, international organizations, foreign central banks of issue, foreign tax exempt organizations, foreign private foundations, and governments of foreign possessions.
It is a 2 page form. There are some interesting parts of this for those who would use it.
I suggest that you download it and read it from this page here W-8EXP Form.
W-8 EXP Instructions
It' is a 6 page instructional for the form W-8 EXP.
Certificate of Foreign Government or Other Foreign Organization for United States
This is a long instructional, and it is best if you download it and read it, rather than get a brief synopsis in this case.
Download the W-8EXP Instructions.