There are four theories.
The first is in the Bible, the Jews came into Canaan after the Moses trek followed by by a victorious conquest of Canaan by Jews. Joshua won the battle of Jericho. The problem with this theory, besides lacking any archaeological evidence, is the Bible’s version of the story has incosistancies.
A second is called the immigration theory. Here, a group came into Canaan and settled without war in the sparsely populated highlands. After becoming established, they grew to dominate the cities. This theory, too, offers no archaeological evidence nor a historical trail.
The third is that a group came out of Egypt into Canaan and eventually became aligned with oppressed Canaanite peasants. These two forces joined, overthrew the oppressors and came to rule Canaan. There is not evidence for this either.
A forth theory, claimed to be the current favorite by modern scholars in the field, is called gradual emergence. That is, what came to be know as Judaism come out of indigenous Canaan over a long period of time. The cult of Yahweh started somewhere in the country and grew to represent a significant portion of the population. This indigenous theory is not the one people enjoy so the mythological story of a great victory it the one that made it into the Bible.
Perhaps we could say number four is the default theory. Since there is no evidence the people of Israel came from anywhere else, they must have originated where they were found.