All purpose flour: Make sure you sift the flour before using. Last thing you need is lumps in your pasta dough.
Semolina flour: Made from a coarse variety of wheat, semolina flour is used for its higher bite and ability sturdy nature which lets the pasta retain its shape while being cooked. While ravioli especially, semolina would be a good option to consider since the raviolis need to retain its shape during the cooking. And of course, sift the flour.