Here is my Suggestion for your question ,

• Formal Environment: If your workplace has a formal dress code, opt for a business suit. For men, this could be a tailored suit, dress shirt, tie, and polished shoes. For women, a tailored suit, blouse, and closed-toe shoes are appropriate.
• Business Casual Environment: If the dress code is business casual, men might wear a dress shirt with or without a tie, dress pants, and leather shoes. Women could choose a blouse or a modest top with dress pants or a skirt, and comfortable but professional shoes.

Your clothes should fit well and be clean and pressed. Make sure your grooming is tidy—this includes hair, nails, and any facial hair.

Keep accessories minimal and professional. A classic watch, simple jewelry, and a polished belt can complement your outfit without overpowering it.

If the promotion is for a leadership position, dressing slightly more formal than usual can convey that you’re ready to take on more responsibility.