My reply to melvinhate:
Let me answer your second question first. It isn’t appropriate to say that “This agency has several deployment to Japan” because the sentence has defective syntax. Also, keep in mind that the adjective “several” requires the noun that it modifies to be in the plural form, in this case “deployments.”
The following alternative reconstructions of that sentence are syntactically and grammatically correct:
1. “This agency has made several deployments of OFWs to Japan.”
2. “This agency has deployed several OFWs to Japan.”
As to your first question, yes, “to” is the correct preposition to use in both of the sentences above, after “several deployments of OFWs” in Sentence 1 and after “several OFWs” in Sentence 2.
“Deployment” is indeed a military term that means “placing troops in battle formation or appropriate positions,” but the word also means the “spreading out or arranging for a deliberate purpose,” as in deploying a work force. It is very much in vogue in the Philippines with reference to the sending of OFWs for employment in foreign countries.