My minor child is visiting the Philippines on his/her own. Does he/she need to present anything to Philippine immigration?

Under Section 29(a) (12) of the Commonwealth Act No. 613 or the Philippine Immigration Act of 1940, for children below fifteen (15) years of age who are unaccompanied by or not joining a parent to be admitted into the Philippines, the applicant's parents must execute a Waiver of Exclusion Ground (WEG), to be submitted at the port of entry. The requirements for WEG may be viewed here:

A WEG is not needed for minors above 15 years old traveling alone.