Version: v4.x
Popup with Marker

Live Editor
const position = [51.505, -0.09]  render(   <MapContainer center={position} zoom={13} scrollWheelZoom={false}>     <TileLayer       attribution='&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'       url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"     />     <Marker position={position}>       <Popup>         A pretty CSS3 popup. <br /> Easily customizable.       </Popup>     </Marker>   </MapContainer>, )
Result