You may have skills that you acquired from your years of experiences in your workplace but you cannot produce certificates to prove such except for the recommendations and employment certificates provided by your employer. Many HEIs are requiring skill-specified certificates that were earned from learning institutions and training centers and most of them accept those that were taken up online.
We have a few suggestions here that may help you.
Create an account with LinkedIn here and complete your profile. Then visit their learning sites here where you can find their free lessons and take up an examination at the end of each lesson. You can then download the certificates that you can use as credentials.
They have one month free trial on premium accounts that you may want to take advantage of where you can find premium lessons. You may continue with the paid premium account at the end of the trial period if you wish.
Google also offers online lessons in different topics. They have free lessons but if you want to earn a certificate, you need to pay a certain amount for each examination that you take up. You may visit their learning site here.
Technical Education and Skills Development Authority (TESDA)
The Philippine government has set up a department that provides free training on different skills where one can earn a certificate at the end. You may visit their website here, and their e-learning site here.