The Westminster Confession was drafted in 1646 and is one of the Reformed creeds of faith. In this confession (chapter III section 1) it reads:
God from all eternity, did, by the most wise and holy counsel of His own will, freely, and unchangeably ordain whatsoever comes to pass
What does it mean for God to ordain all things that come to pass?
That is frustratingly difficult to answer. The word “ordain” carries the meaning of “to decree, “to set (something) that will continue in a certain order”. How God ordains all things is closely related to how one understands God’s sovereignty. There are 4 major models (outlined in this Parchment & Pen post), describing different ways in which God may exercise His sovereignty.