Yes McDonalds does put sugar in their burgers.
McDonald's has been putting sugar and salt in their burgers since they first opened and in the year 1989 McDonald's would put about 2.6 grams of sugar in their hamburgers and now in 2020 they put 10 grams of sugar in their burgers.
McDonald's hamburgers and food is okay in moderation but when you eat too much McDonald's Hamburgers and food you can get unhealthy and could gain weight.
It's not McDonald's fault though that you get unhealthy or gain weight as it's a choice to eat their food.
I only eat McDonald's food when traveling or maybe once or twice per week when I'm hungry and out shopping or I just don't want to cook for me or the kids that day.
But we don't eat a lot of McDonald's food and we eat healthier food at home.