Marriage and Working Visa

My fiance and i have been together for about 1 1/2 years. I am a citizen and he came to the United States when he was about 8years old with his father who is a citzen. He has applied for residency but he needs his father who is not able to help him right now.

Now we want to get married and move in to our own place, what is the best way to go about this, we don't want to just jump into it blindly. Should we apply for k3visa or is there something else we should do?

and also how can we get a work permit, because we would like to move in together, him working would help that dream come true.

If your fiance is lawfully in the United States you should be able to marry then file an I-130 petition for Alien Relative, and I-485 application for permanent residence.