It is not native to English speakers. It is used by French and Creole speakers. Planify, a verb, means to plan, but often has economic nuances to it. Planification is a noun, referring to the process of planning or organizing, again, often with regard to economic organization in French.
If you are planning a party for the weekend, in English, you would simply say, "I am planning a party for the weekend." English speakers would know what you mean if you said you were planifying a party, but they would never say it that way.
Used as a noun, the state highway commission would have a Planning Department, not a Planification Department.
Also for English speakers, the word Department in French or Creole has the additional meaning of an organizational jurisdiction similar to a named state in American English (like Ohio, or Florida, or North Dakota, West Virginia or South Carolina, or Texas). In Haiti the Nordest Department is the name of the northeastern state (a smaller organizational jurisdiction of a country), specifically named and translated as the Northeast State, the one which borders the Dominican Republic at the Atlantic Ocean, aptly, in the northeastern part of Haiti. Their land measurements in the Department are measured by hectares, not acres. American state, county and township jurisdictions are broken down into acres. In the American state of Louisiana, counties are called parishes.