what does this sentece means 你是边度人?
This is a Cantonese  way of saying "Where are you from", equivalent to the Mandarin way of saying 你是哪里人. You could answer it by saying 我是____人, meaning, "I am from ___" (filling in the blank with where you're from; e.g. if you're from the USA, you would reply 我是美国人). Literally translated, it means you-are-where-person?

In Cantonese, there is a difference between the spoken form and the written form. What you've written is usually what is spoken (but I think it's usually 你係邊度人). More commonly, in writing, you would use 你是哪里人 instead of 你是边度人.