1 month is when baby can hear sound, they can grab with gusto now, they don’t yet have the hand-eye coordination to reach for an object you pass in front of them. However, they are still pretty small and like to sleep.
Your baby has been able to recognize you, they will probably continue to smile at strangers, they would show you more emotion or facial expression than they are in 1 month or newborn stage. They have strong neck and back to do push up pose, they are more feel like to smile, they would even give you unexpected poses as they like.
When baby turn to 4-8 months, they start becoming more active. They can sit with support, they would have even more expression and more interaction as they start understanding what you are telling them.