I keep getting the same text/calls from friends and I don't know what it does

Shortly after I get a message like this some random Sim shows up at the front door. You can invite them in and do an introduction. So watch you front door after you get the message. Sometimes they just barge in and ask to grow friendship based on interests or some other message: nice to meet you let's hang out. Like when neighbors or friends show up at your apartment in City Living. Oh, I was in the city today and I'm crashing here or something like that. I don't remember the exact wording.