I coped and pasted this from the NIV out of Matthew 18:
15 “If your brother or sister[b] sins,[c] go and point out their fault, just between the two of you. If they listen to you, you have won them over. 16 But if they will not listen, take one or two others along, so that ‘every matter may be established by the testimony of two or three witnesses.’[d] 17 If they still refuse to listen, tell it to the church; and if they refuse to listen even to the church, treat them as you would a pagan or a tax collector.”
I have always assumed that the churches formed AFTER Jesus’ death, but here we have Matthew quoting Jesus, who speaks as though formal “preaching places” were common during his ministry. Not being a biblical scholar, many hypotheses suggest themselves to me that would account for the nature of Matthew 18: 15-17. For example:

1. This quotation is gist-accurate, which is evidence that Jesus might have formed churches in Galilee.
2. This is a forgivable anachronism in Matthew’s account. Writing decades later, Matthew referred to a collection of believers as a church.
3. Matthew is pushing a policy that he feels will work and he is writing it into his gospel to enlist the authority of Jesus for the strategy.
4. Some copier at a later date is pushing a policy that he feels will work and he is writing it into Matthew’s gospel to enlist the authority of Jesus for the strategy.

I am sure there are many others, perhaps more plausible than these. Suggestions and corrections welcome.