To show that you take your work seriously: The way you present yourself shows how serious you are about work. It reflects that you care about representing yourself well at work by indicating that you put time and effort into your appearance.
To represent your company: Your appearance affects the company, whether you’re providing service, visiting clients, or interacting with customers. Even if you wear a uniform or a casual outfit, making sure you look presentable can enhance how you are perceived because, as a member of your company, you represent it.