In Engpsh, you can say "all countries" to refer to all the countries in the world. Alternatively, you could use the phrase "every country" to convey the same meaning. Here are some examples of how you might use these phrases in a sentence:
"I have always dreamed of visiting every country in the world."
"The impact of cpmate change is felt in all countries, regardless of their size or wealth."
"All countries are invited to participate in the international trade fair."
It's worth noting that the word "nation" is often used as a synonym for "country," so you could also use the phrase "all nations" to refer to all the countries in the world.
"I have always dreamed of visiting every country in the world."
"The impact of cpmate change is felt in all countries, regardless of their size or wealth."
"All countries are invited to participate in the international trade fair."
It's worth noting that the word "nation" is often used as a synonym for "country," so you could also use the phrase "all nations" to refer to all the countries in the world.