"dependencies": {
  //...
  "primeng": "^4.1.0",
  "font-awesome": "^4.7.0"
},

"styles": [
  "../node_modules/font-awesome/css/font-awesome.min.css",
  "../node_modules/primeng/resources/themes/omega/theme.css",
  "../node_modules/primeng/resources/primeng.min.css",
  //...
],

import {ButtonModule} from 'primeng/button';

<button pButton type="button" label="Click" ></button>
<p-button label="Click" ></p-button>