Plant cell has a cellulose layer surrounding the cell membrane called the cell wall. Cellulose makes up about 40% of the dry mass of the wood.

To make paper, wood is processed into pulp either by grinding, heat-treating, or chemically digesting. During the process, wood is broken down to cellulose fibers. Pulp is then spread out and let dry. The fiber forms a network during the process. This network is what we call paper.

The cells are destroyed in the process of making paper and will not be found in paper.

The cells are broken down when the tree is turned into paper. The wikipedia article about sawdust talks about this.

The tree rings we see when a tree is cut down are dead xylem cells that stack end-to-end and carry water in sap up the tree.