Was just curious about how the manufacturing of beer is done. Can it be made at home also?
It's possible to make almost any beer at home; this hobby is known as Home Brewing and even has a Stack Exchange Community around the topic.
Most beer falls into two major categories: ales and lagers. Ales are easier to make at home because the beer can ferment at temperatures that do not require special equipment.
Budweiser is a lager; lager beers require additional equipment to keep the beers fermenting at very specific low temperatures. So while it is certainly possible to make beers like Budweiser at home, few choose to do so because of the added expense and level of difficulty of doing so.
You can certainly brew beer at home that is similar to a commercial recipe, but unlikely one that will pass for exactly the same thing. First, the exact recipes are trade-secrets, and while you can guess at the quantities of ingredients, boil times, etc, you likely won't get them exactly the same. Additionally, the ingredients you use aren't going to be exactly the same, and by far the biggest difference is likely to be in the water. The mineral content in your water will be different from theirs, for instance, and this will have an effect on the flavor.
That said, brewing beer shouldn't be able slavishly replicating something you find on the store shelves...It should be about experimenting until you find the recipe that is perfect for your particular tastes.