A 2-month-old baby's weight should be increasing steadily and they should start sleeping for longer stretches. They'll also be developing their neck muscles more, and they might be able to lift their head during tummy time. They may spit up clear liquid occasionally, but it's not usually a cause for concern. Instead, it's more like a warning system that lets them know they have overfed or have something wrong with their stomach.
If a baby spits up clear liquid, it could be saliva or secretions that they swallowed before they burped. This can happen when the ring of muscle that connects the esophagus to the stomach opens to let in milk, but then it closes too soon. If the milk builds up too much it will come back up, which is referred to as reflux.
Drooling is another common baby behavior that's often confused with spitting up. However, babies usually outgrow drooling as they get older. If a baby is teething, it can be more painful for their digestive system, and this is why they might be spitting up.
Some babies might spit up more than others, but the amount of clear liquid is usually not very much. It might be 1 or 2 tablespoons at a time. To reduce spit ups, try not overfeeding, keep your baby in an upright position after feeding, help them to burp after each meal, and thicken their formula as recommended by your doctor.