I am from Nigeria, I would like to know how to add my debit card and billing information on my
ewallet in Windows Phone 8.
Unfortunately in some countries like Nigeria and Brazil you can't add you
debit card as a payment option to buy apps on the Store.
Alternatively you can change the
settings and use a prepaid credit card from that region.
I'm currently using my phone in the USA region and use an American Express prepaid credit card to purchase apps.
Another alternative is you buy gift cards from Microsoft but is unlikely it will work in all countries too (Here in Brazil this became an option just in January 2014)