I have a 12 weeks old pomchi who pees outside fine but has a problem pooping outside. He gives us almost no warning before just going, I have been just trying to take him out when he wakes up, eats, etc and he seems to get it, but I was just wondering if he will naturally start to give us more warnings or has be gotten used to be just taking him out

He is only 12 weeks you have to train him. At least he got the pee part down so far.

At 12 weeks old it's amazing that he's already trained to pee outside. A puppy that young can't hold it for long, and can't really give a warning since he doesn't have to go one second, and does the next.

Keep up the potty training. At his age it's best to take him out for a potty brake around 10 - 20 minutes after he eats. Choose a potty word, and repeat it over and over until he goes. When he does potty outside, tons of praise, a treat, let him know that he did what you want him to do. When he potties inside, a firm no and take him directly outside. Even if he's in the middle of pooing, pick him up and out you go, use your potty word, and when he finishes outside, lots of praise.

He's a baby, and it will take some time before his body can catch up to what he knows you want him to do. Positive reinforcement, lots of praise, no yelling, no screaming, all positive, that's the way to go. But it's not going to be instant. He's still very young.

It's recommended to start potty training as soon as you bring your puppy home, but don't expect him to really be reliable until he's at least 4 months old. At this stage it's just reinforcing behavior until he's old enough to consistently do what you expect. Even four months is pushing it, it will likely be closer to 6 months before he's completely potty trained.