Do a Nigerian need invitation letter to visit Philippines?

Do i really need to send invitation letter to a frend who wants to go here in philippines?? He is nigerian.and how is the process?? Pls..im so confused someone tells me i dont need to send him..some says i should.

Hi there..under Nigerian immigration laws you have to send an invitation letter .even expatriates do send letters when applying for TWP or RESIDENCE visa.

I believe that it is in all countries immigration rules for a resident to send an invitation letter to an intended foreigners who want to visit and especially when he/she claimed to know or have a contact in that country.
Therefore, for you to acknowledge his/her coming, you will need to send it.

And also, I will like to know his purpose of coming if you can share....