Here in Venezuela (at least in my city) it's a mixed thing. It's not a tradition to decorate homes or carve pumpkins, though a very small number of people do (most often just for themed parties).
Some stores have been decorating for Halloween for as long as I can remember, though it has become more common in the last couple of decades.
Clubs often throw themed parties for Halloween, this is very common.
When I was a kid, children would not wear costumes for Halloween, but I think some do now.
Trick-or-treating has never been a thing here... and nowadays it's just impossible, this country is not safe enough to have children knocking on people's doors, and with our economic crisis, most Venezuelan families can't afford to buy sweets for themselves, even less to give away to strangers.
Attitudes toward Halloween are mixed too, some think it's fun (me included), some see it negatively as cultural invasion and some are just indifferent to it.