JSFiddle - React, Tailwind, and code Playground

HTML

<link href="https://fonts.googleapis.com/css2?family=Montserrat:wght@400;700;900&family=Ubuntu&display=swap" rel="stylesheet">
<p class="w-900">Hello 900</p>
<p class="w-700">Hello 700</p>

CSS

body{
font-family: 'Montserrat', sans-serif;
}

.w-900{
font-weight: 900;
}

.w-700{
font-weight: 700;
}