It's almost similar process when opening a bank account, the stock-brokerage staff will require you to fill out and sign the application form called Customer Account Information Form (CAIF), trading agreement, and submit the following documents;

Present copies of any two (2) of the following:
•    Passport
•    Philippine driver's license
•    SSS ID (1999 credit card type only) 
•    Company ID if employed by top 2500 corporations (with photo)
•    Major credit card with picture
•    Senior citizen's ID
•    Birth certificate

Present any latest copy of any of one of the following in the applicant's or spouse's name:
•    Current utility bills
•    Credit card statement
•    Club membership bill
•    Bank statement

Depending on your stockbroker, you may be also asked to provide an initial cash deposit in order to begin investing in the stock market.
For Overseas Filipinos, the simplest and most convenient way of investing in the Philippines stock market is to open a stockbrokerage account with an online stockbroker or apply directly to any overseas branches of Philippine banks that are affiliated to any of the active stockbrokerages in the PSE. Through the internet, overseas investors will be able to access the Philippine stock market and trade stocks real-time.

Lastly, overseas investors can also participate in the Philippine stock market through mutual funds, and index and variable-linked funds offered by various financial institutions such as banks, mutual funds management companies and insurance firms in the Philippines.