hi everyone

hope somebody can help me.
i was hopeing to bring a boy to spain for a 2 week holiday in October
whats the process to get a visa for him, he is at school, 19 years old
from chiang mai
do i buy the tickets this side or semd him the money to buy them that side.
Ive never done this before, and either has he
any advise would be good thankyou