I've seen other people do it, but I don't know how people do it. So, how do I prevent people from changing the text?
I'd suggest making a Text Label if that is what you mean; but otherwise for a textbox, you can make a script such as this(put it in text box):
str = script.Parent.Text script.Parent.Changed:connect(function(change) if change =="Text" then script.Parent.Text = str end end)