I am Filipino. I have a friend that is a citizen in UK. He told me that I will visit him and he will cover all of my expenses when I am in his country. So what kind of visa should I apply for? And what are the requirements?
Note: the bulk of this answer is applicable to any visa-national who wants to come the UK as a visitor.
Based upon the information you gave, you should go to Visa4UK and create an account. Then fill out the second page of the application like this...
The programme will know what to do after that. It means you are applying as a 'Standard Visitor' and your application will be assessed under Appendix V of the rules.
Both you and your bf should study those rules before starting and determine if you can qualify. If he is to act as your sponsor, he will need to submit all of the evidence that the applicant would normally submit (in addition to all the evidence the applicant should submit).
Also, it is critically important to read the guidance notes before starting. After reading those, you may have more questions.
Once you finish the application you will see some screens asking you to print out your application and take it to their commercial partner to get your biometrics.
As I understand it, you are unemployed and reliant upon a sponsor that you haven't met in person before. You are also a Philippine national which is a high risk nationality. In the absence of a really spectacular application, I would expect a refusal on V 4.2 (a) will leave the UK at the end of their visit; and V 4.2 (e) must have sufficient funds to cover all reasonable costs in relation to their visit without working or accessing public funds.
Additionally, I would expect them to disqualify your bf on V 4.3 (a) have a genuine professional or personal relationship with the visitor;
You may wish to get your sponsor to instruct a UK solicitor for a consultation.
General notes about Manilla The British embassy in Manilla operates a big, BIG visa section. Among all the various descriptors you could apply to the visa section, 'lenient' is not one of them. They will decide an application within 60 days with a median at around 15 days. Beware of scam artists and bogus visa agents.