I assume this is your first application to the UK and perhaps your first trip outside of Philippines.
Your partner should prepare documents showing:
- His current status in the UK (as he is a UK citizen, a passport copy would suffice).
- Proof of income (for example, pay slips or tax returns).
- Proof of residence (for example, title deed to a property, rental contract, rental slips)
- Letter affirming the nature of your relationship, the length and purpose of your visit and specifically what costs he is willing to bear for your trip. For example, the letter can state he is covering your room and board, the cost of your flight, plus any daily expenses you may incur during your stay.
You should prepare the following documents, which are required for any standard visit visa application:
- Photographs with a white background.
- Copy and original of your passport - which should be valid for 6 months after your trip.
- Proof of employment, such as a salary certificate that details your length of employment, your position (job title), your salary.
- Bank statements showing income and expenses. Please do not try to "borrow" money for your trip just to inflate your bank balance. This is called funds parking is a very common reason for rejection of applications as it is considered a form of fraud.
- Application for a Standard Visit Visa
- Any fees
- Flight reservations for the duration of your trip
You can find out exactly what all documents are required from https://www.gov.uk/apply-uk-visa including how and where to apply for your visa and any fees as well. This is an official UK government site - try to avoid others that may be scams just to charge you fees.
As you and your partner are not in a legal relationship (ie, you are not in a civil partnership) you can only apply for a visit visa.