JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" placeholder="test" />

CSS

input { 
  text-transform: capitalize;
}
::-webkit-input-placeholder { 
    text-transform: none;
}
:-moz-placeholder { 
    text-transform: none;
}
::-moz-placeholder { 
    text-transform: none;
}
:-ms-input-placeholder { 
    text-transform: none;
}