I have a sister I'm not very close to and I'm trying to mend our relationship

Her and I have really not spoken since we were children, but my husband's only sister just died and it really put into perspective for me that I should work on being closer to my sister. I just don't know how to reach out. I have her number from some group messages with my mom (who I am casually close to, we probably speak once a month or so.) We are so not close that she did not come to my wedding and we haven't physically seen each other since a Christmas about 5 years ago. Should I text her, set up a call? What do I even say?