Yes it's normal for a toddler to play with their private parts and there's nothing to worry about if they do.
But if the toddler is playing with their private parts in public or around other people and family then you need to let the toddler know that it's not good for them to play with their private parts in public or around family.
Let the toddler know it's okay to play with his or her private parts but only in private because that's why private parts are called private parts.
Nobody should be able to see the toddler playing with their private parts.
My mom caught me years ago when I was 3 masturbating as a male toddler and she scolded me for it and would spank me if I did that.
But you should never scold or spank your child just because they are masturbating or touching their private parts as it's very normal.
There just needs to be rules set as to when and where it's appropriate for the toddler and child to masturbate or play with their private parts.