"I am from" in Mandarin
Here is a very simple question.
To say "I am from (country, city) can I use "我来自" and "我是从"?
Are both correct? Are both used colloquially?

Question

Answer

If you want to you “我是从” it’s nevertheless more natural to say 我是从××来的, or you can say 我是××人, or 我来自××.

Answer

The direct translation will be: 
I am from = 我是從____來的
I come from = 我來自______

EX: I am from Brazil (我是從巴西來的)
       I come from Brazil (我來自巴西)

However, as Demian puts, it is more nature to say 我是_____人 (EX: 我是巴西人)

Answer

'I am from' means 我是從 better than 我來自.
You can use "I come from"  to represent "我來自"