That depends on whether you’re a pretribulationist, a posttribulationist, a midtribulationist, or a modified or full preterist. According to the classic historical Christian eschatological formulation, people go to Heaven or Hell at the time of the Last Judgment, after various elements of angel-devil warfare and disasters over the Earth (see Revelation for details). But according to the belief first espoused by Darby and promoted by Jenkins and LaHaye in their popular novel series, Jesus shows up first, before all the warfare and catastrophes, does not descend to Earth, but rather calls to Himself all the True Believers, everyone else getting to live through seven years of general mayhem (and presumably having opportunity to repent and get counted as a Good Guy at the Last Judgment).
So the result according to their scheme is that the True Believers get caught up unexpectedly and sent to their Heavenly reward, while the rest of us get to schlep through the Great Tribulation.
Ergo, the “In case of Rapture, this car will be unmanned” bumper stickers and the cutesy messages like “If you’re Raptured, can I have your car?”