Annulment Based on Presumed Death requires four years absence
Using an Annulment Based on “Presumed Death” is an easier way to get annulled, BUT, if you were to later apply for a visa to go to another country, especially the US, the Embassy, during the visa interview, may want extensive evidence that the absent spouse was truly considered deceased. If you have already checked with the US embassy, and have written documentation, then that should be sufficient for them, or other countries embassies.
The Philippines Family Code, specifically Articles 41 to 44, deals with the declaration of presumptive death for purposes of remarriage.
[3] Proof required that petitioner tried to look for the missing spouse
The court will however require the petitioner to present proof that he or she exerted earnest and diligent efforts to locate the whereabouts of the missing spouse. These efforts include asking the police or NBI for help in locating the missing spouse, using the media like newspapers or radio, etc. The court will deny the petition if the petitioner cannot present such evidence of earnest and diligent efforts to locate the missing spouse.
The Family Code provides for a period of four years (ordinary absence) for a person to be able to go to court and file a petition for declaration of presumptive death of the missing spouse.
Source: famli.blogspot.com/if-husband-and-wife-have-not-seen-each