If you are wondering that how messages come on your smartphone, in the name of your friends and relatives on Snapchat, then let us tell you that this happens when the scamster hacks the ID/Number and account of the people you know and then you Messages come from these ID's
If you want to protect yourself from this scam, the first thing to do is beware of such texts. Also, if someone you know receives a message for help, instead of replying to it, call first so that you can confirm that the message came from someone you know and not a thief. Do not share your personal information over text under any circumstances.