Hi myan_naym, welcome to the forum
As a start please take a look here:-
http://filipinaroses.com/showthread....-A-quick-guide
http://www.vfs-uk-ph.com/index.aspx
Your fiance will need to prove adequate accomodation and financial support.
Financially, and only as a guide, he will need to prove about £103 per week disposable income after all key payments (such as Rent/Mortgage/Council Tax etc)
Lots of threads here on this site to help you.
Any specific questions just fire away.