Resident us card(green card)

Do you intend to take your wife to the USA?  If she is approved for a spousal visa then she can go to the USA and get a green card and register with SSA.  Not sure what the SSA  deal is for a nonresident alien.

Our intention continue living here in the Philippines not going back to the us unless to visit.

I believe if you file form SS-5, application for a SS number, at a local US consulate you should be able to get her a number.  For tax purposes you will want to treat her as a resident alien, you are allowed to do this, without her ever having been in the USA.  If you cannot get a SSN, you need to get her a ITIN, a tax ID number.  You need either a SSN or ITIN to file your 2018 income taxes as married filing joint.  Otherwise you need to file as married filing separate.  If you file the joint return then the standard deduction is $24,000, but for married filing separate it is only $12,000.  If you file a joint return you need to claim all of your world income for both of you.  You may want to PM me if you have any specific US income tax questions.