Short answer: In English, common, respectful options are “Happy Veterans Day” or “Thank you for your service.” If you’re aiming for gratitude rather than a direct well-wishing, you can say “Thank you for your service.” context and variations

• Informal or casual: “Happy Veterans Day!” (widely understood, upbeat)
• Grateful tone: “Thank you for your service” (more formal and widely used on this day)
• If addressing a specific veteran: “Happy Veterans Day, and thank you for your service, [Name].”
• For messages to a group or broader audience: “Thank you to all veterans for your sacrifices and service.”

Tips for usage

• In American contexts, it’s common to pair a greeting with thanks, e.g., “Happy Veterans Day. Thank you for your service.”
• If you’re writing a card or formal message, leading with gratitude is often most appropriate: “Thank you for your service on this Veterans Day.”
• Be mindful of audience; some people prefer “Happy Veterans Day” while others appreciate the explicit gratitude.

If you’d like, tell me the language or audience (e.g., Spanish, German, casual friend, official letter), and I can tailor a precise phrase.