Well this is a vast question, yes they can. However, it is not all that simple. Start off with the fact that we don’t have the technology to access Earth-like planets we could live on. Over forty planets that could be habitable have already been found.
Reaching the exoplanet might only be half the problem. Will the planet already be suitable for life? Or, will we need to terraform it, manipulate its environment, so we can mould it into our Mother Earth? Will we be wiped out by some unknown disease we have no resistance to—as happened to the aliens in War of the Worlds. Will we be able to adapt to the environment? What about building a colony outside our planet which will be completely independent of Earth? Eventually yes, on a planet with the right conditions, but let’s get there first.