Is it emphasize on or emphasize to?

Answer:
Neither. It is "emphasis on". (The verb to emphasize is transitive and has a direct object.)

Examples: "The emphasis on promotion sometimes overlooks actual education."

Examples : "At the board meeting, parents emphasized the need for more school funds,"
First answer by Froggy ish 122. Last edit by Froggy ish 122. Contributor trust: 2 [recommend contributor recommended]. Question popularity: 2 [recommend question].