I spent a little while just now thinking about how to answer this, going back and forth between formal moral codes like humanism and stoicism and contemplating the value in Buddhist philosophy and the LaVeyan Satanism code of conduct. But, realistically, I've never looked to any structured ethics for how I live life day to day. My personal philosophy can be summed up in a few pithy statements.
Obviously these are oversimplified and lack any semblance of nuance, but the core of how I live my life comes down to these basic principles.
My moral code is simple and can pretty much be summed up as "Don't be an asshole."
Care for your family and friends, help strangers when you can, don't take what isn't yours, don't knowingly and intentionally bring harm to another person, and try to leave the world a better place for future generations. Strive to treat everyone with the decency and respect you yourself would hope to receive, whether or not you do receive it.
I believe in the Golden Rule, treat others the way you wish to be treated. It's a good rule for all people of the earth and if we lived by this code there would be no hate, Bigotry or wars. Actually the Golden Rule is much more ancient than the bible; this simple plilosopjy is found in almost all religions in the world since they started writing down their beliefs.
Over the years, I'm 70, I have developed a strong sense of empathy and that is my moral compass. I put myself in other people's shoes and think about what they may need and then I see if I can help in any way. I am an atheist and a humanitarian and I feel that helping others when I am able is my moral responsibility. I do it because I know it is the right thing to do and not because I fear hell or am trying to curry favor with some god.
I love when people ask me if I have morals because it's just funny to think the only reason I'm not going out and killing people is because of my religion and if you don't have one well you don't have morals I just think it's hilarious and a stupid question because you don't get your morals from religion you get it from yourself or that's what I think anyways and if the only reason you're not going out and killing people is because of your religion well you shouldn't be questioning my morals
I feel that first and foremost you should do no harm. You do not steal, kill, rape or torture. Basically so unto others as you would have them do unto you. Treat others worth the same dignity and respect that I would expect. You don't need religion to know what is right and what is wrong.
My Grandmother used to tell my mother, "Before you do anything think about how you would like to read about it in the paper". So, I don't lie, cheat, steal, and I try not to hurt anybody. I joke that most Atheists are better Christians than most Christians. One of those 'it's funny because it's true" things.
This is a weird question - it assumes that religious people follow a "moral code" from whichever "holy" book they follow - but in fact they cherry-pick the bits they want to follow (no killing, stealing, etc) and ignore the bits they know are wrong (kill your children if they're rude to you, go to hell for wearing mixed fibres or eating shellfish).
So as an atheist I use the same innate moral code they do - I use my reasoning to know what is right or wrong - and don't pretend a magic person in the sky had to tell me what to do.
I do not follow a "moral code", I follow a set of principles from which moral action can be derived. "Moral codes" are rules set by people who believe that everything can be cut down to black and white, right and wrong, good and evil on simple terms.
The Laws of Moses are a "code". Morality is not.
I do what I can to objectively make the world a better place. Aside from the Golden Rule, there's also this: When I woke up this morning, the world was not good enough. So rather that sit on my ass, I'm going to take a little responsibility for making it better, and do some things every day that will make other people's lives a little better, and a little easier. Because the world isn't going to get better if no one does anything to make it better.
I was indoctrinated into the Catholic religion but my moral code partly came from my father who was quite strict about lying and stealing. Most of us, save psychopaths, have a conscience that we may or may not listen to. Morality is fluid and situational. For example, we may think it is wrong to lie but if the Gestapo came to arrest someone we were hiding, we would do our best to save the person. Therein, is one of the main failings of a fixed morality.