Is it safe to microwave water for hot coco?

I usually heat milk in the microwave for hot coco. But I bought a new brand and it says to add hot water and you're done. But i dont have time in the morning to boil water on the stove, so is it safe to microwave water? And how long should i microwave it for? Also, could i use milk like i normally do? The instrutions dont say anything about milk, it just says "add hot water and stir". Anything will help thanks! 🙂