JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="prenom" value="cacac" placeholder="Prénom"/>

CSS

::-webkit-input-placeholder {
   color: #000000;
}

:-moz-placeholder { /* Firefox 18- */
   color:  #000000;  
}

::-moz-placeholder {  /* Firefox 19+ */
   color:  #000000;  
}

:-ms-input-placeholder {  
   color:  #000000; 
}