There are websites that specialize in that. One of them asks you to smear some saliva on a little stick, then they'll analyze it and tell you where your ancestors came from.
And then there are others that will simply examine your family tree, looking up public records. Of course the two kinds of research give you two kinds of answers. The one will tell you where your family came from, going back quite a few generations, whereas the other will tell you who your more recent ancestors were and where they lived.
But with a lot of investigation, you can get both. My in-laws have a family tree that goes back to when the Romans abandoned what is now England, leaving it wide open for the Germanic tribes to conquer the original Celtic population. They turned the country into "Angle Land," named after the Angles, one of those German tribes. The in-laws even have the names of many of those ancient ancestors.
"England" and "English" are simply phonetic variations of "Angle Land" and "Anglisc," as the language twisted and turned over the centuries.