My six year old step daughter does not like our newborn and I have even seen her hit her. how do I tell my husband about it?

I don't think telling your husband would solve the issue, but you can inform him and not complain so that he too remains vigilante and also think out of ways so that your step daughter can get over the insecurity that she is going through after the arrival of the new baby. I know that little baby requires your attention all the time, but you involve your elder daughter too so that she doesn't feel left out. For example, if you are feeding her, tell her that you are such a sweet big sister and if were not around you wouldn't know how you could look after the little one. Tell her to hold the feeding bottles under your guidance, let her get the little one's diapers. When the little girl is sleeping, you can have your elder daughter be by your side, and read stories for her. Three of you can go together to the park and let her walk the pram. Both your husband and you together will have to be with her and give her more attention so that she feels important. The little one anyway wouldn't know whom you love the most but your step daughter can make up her mind by seeing whom you are attending more to. So, the best way is to involve her in everything that you do for the little one, and keep telling her, that you could not have managed anything without her. https://www.empoweringparents.com/article/blended-family-the-5-secrets-of-effective-stepparenting/