Apart from IPF (International Pen Friends), there is another platform where one can get snail mail friends and / or email friends.
I managed to get quite a number of snail mail friends from Global Pen Friends. Unlike some other sites, Global Pen Friends gives some credits to new profiles created. Or if you wish to make use of the Premium Members Benefits, there are some fees involved.
If you are keen, explore their website and begin your search for international friends via email or snail mail. All the best!