how to register original songs ?

[Al Ram]

Friends

My 30 year old son has some original songs he has composed and producing . . lyrics, melody, arrangement, etc.

He asked me but I did not know . . . so i am asking here . . .

Anyone knows how to register songs ?   
a) USA
b) Mexico
c) internationally
d) all of the above

The idea of course is to protect his rights before publish/distribution.

Your expertise is welcome.

thanks in advance.

[SciNote]

In the U.S., you can register original works using the U.S. copyright office website of www.copyright.gov