Because you are not a minor already, you need to find an employer which supports your work permit and ARC, if you want to get an ARC and work in Taiwan. After you get a work permit, you can get your ARC based on the work permit. Or, if you would find a Taiwanese spouse, you can get an ARC based on the marriage, and can work without a work permit.
Your country has an organization for people like you.
Philippine Overseas Employment Administration
http://www.poea.gov.ph
Status of Recruitment Agencies as of Apr 20, 2018
http://www.poea.gov.ph/cgi-bin/agList.asp?mode=act