Hi Renato. There’s no difference in meaning for manmade and man-made. Some words like this is English start with a hyphen and then, over time, lose the hyphen because of the frequent use. Either spelling is correct. Hope that helps!

Miss Palmer is exactly right. I would add that when native speakers have a question like this, we use a dictionary. In fact, you will find that the more a person knows about English, the more they use a dictionary. A no-cost online dictionary is fine. US and UK speakers speak the same language, but there are slight difference in usage--just like the difference between Brazilian and peninsular Portuguese--so use whichever is appropriate. A US dictionary, https://ahdictionary.com/word/search.html?q=manmade show us "manmade or man-made." Since both are listed, both are OK. Since "manmade" is listed first, it's more common. However, I see that a British dictionary only lists "man-made." Apparently the British are a little more conservative and old-fashioned than US speakers, and they are continuing to use the hyphen longer than we are. https://www.lexico.com/en/definition/man-made