Islam question: What makes meat Hallal?

Factual Questions
1

I heard something like “they have to drain all the blood out” or “the animal has to be killed in a humane and painless way”.

2

Here is more info than you’ll ever need about what makes meats halal or not. Like kosher, it’s a set of rules designed for hygeine and food safety.

3

Thanks for the link.

4

There are those who would argue with your second sentence.
Peace,
mangeorge