Normative social influence occurs when an individual goes along with the majority because they don't want to be excluded from the group. This occurs due to compliance as people are scared of being rejected. For example a teenager may smoke along with their friends to be a part of it and look cool.
Informational social influence is when an individual actually believes the facts and information given by the majority because people believe that others have more information than we do. This occurs due to internalisation where the individual strongly hold the opinions of the majority and believe them to be correct. For example during elections people may discuss various of candidates, this could lead a person to believe that others know more.