1. First, go to the Google sign-in branding guidelines page at the link here.

2. Click on Download files.

You should see a folder in your Downloads folder as shown below:

3. Double click on the folder. Go to google_signin_buttons > web > vector.

4. Inside the vector folder, rename btn_google_dar_normal_ios to login.

5. Copy login.svg and paste it inside the public folder of your React project.

6. Click on login.svg inside your React project and replace the code with the following code:

<svg width="46px" height="46px" viewBox="0 0 46 46" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:sketch="http://www.bohemiancoding.com/sketch/ns">
    <title>btn_google_dark_normal_ios</title>
    <desc>Created with Sketch.</desc>
    <defs>
        <filter x="-50%" y="-50%" width="200%" height="200%" filterUnits="objectBoundingBox" id="filter-1">
            <feOffset dx="0" dy="1" in="SourceAlpha" result="shadowOffsetOuter1"></feOffset>
            <feGaussianBlur stdDeviation="0.5" in="shadowOffsetOuter1" result="shadowBlurOuter1"></feGaussianBlur>
            <feColorMatrix values="0 0 0 0 0   0 0 0 0 0   0 0 0 0 0  0 0 0 0.168 0" in="shadowBlurOuter1" type="matrix" result="shadowMatrixOuter1"></feColorMatrix>
            <feOffset dx="0" dy="0" in="SourceAlpha" result="shadowOffsetOuter2"></feOffset>
            <feGaussianBlur stdDeviation="0.5" in="shadowOffsetOuter2" result="shadowBlurOuter2"></feGaussianBlur>
            <feColorMatrix values="0 0 0 0 0   0 0 0 0 0   0 0 0 0 0  0 0 0 0.084 0" in="shadowBlurOuter2" type="matrix" result="shadowMatrixOuter2"></feColorMatrix>
            <feMerge>
                <feMergeNode in="shadowMatrixOuter1"></feMergeNode>
                <feMergeNode in="shadowMatrixOuter2"></feMergeNode>
                <feMergeNode in="SourceGraphic"></feMergeNode>
            </feMerge>
        </filter>
        <rect id="path-2" x="0" y="0" width="40" height="40" rx="2"></rect>
        <rect id="path-3" x="5" y="5" width="38" height="38" rx="1"></rect>
    </defs>
    <g id="Google-Button" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd" sketch:type="MSPage">
        <g id="9-PATCH" sketch:type="MSArtboardGroup" transform="translate(-608.000000, -219.000000)"></g>
        <g id="btn_google_dark_normal" sketch:type="MSArtboardGroup" transform="translate(-1.000000, -1.000000)">
            <g id="button" sketch:type="MSLayerGroup" transform="translate(4.000000, 4.000000)" filter="url(#filter-1)">
            </g>
            <g id="button-bg-copy">
                <use fill="#FFFFFF" fill-rule="evenodd" sketch:type="MSShapeGroup" xlink:href="#path-3"></use>
                <use fill="none" xlink:href="#path-3"></use>
                <use fill="none" xlink:href="#path-3"></use>
                <use fill="none" xlink:href="#path-3"></use>
            </g>
            <g id="logo_googleg_48dp" sketch:type="MSLayerGroup" transform="translate(15.000000, 15.000000)">
                <path d="M17.64,9.20454545 C17.64,8.56636364 17.5827273,7.95272727 17.4763636,7.36363636 L9,7.36363636 L9,10.845 L13.8436364,10.845 C13.635,11.97 13.0009091,12.9231818 12.0477273,13.5613636 L12.0477273,15.8195455 L14.9563636,15.8195455 C16.6581818,14.2527273 17.64,11.9454545 17.64,9.20454545 L17.64,9.20454545 Z" id="Shape" fill="#4285F4" sketch:type="MSShapeGroup"></path>
                <path d="M9,18 C11.43,18 13.4672727,17.1940909 14.9563636,15.8195455 L12.0477273,13.5613636 C11.2418182,14.1013636 10.2109091,14.4204545 9,14.4204545 C6.65590909,14.4204545 4.67181818,12.8372727 3.96409091,10.71 L0.957272727,10.71 L0.957272727,13.0418182 C2.43818182,15.9831818 5.48181818,18 9,18 L9,18 Z" id="Shape" fill="#34A853" sketch:type="MSShapeGroup"></path>
                <path d="M3.96409091,10.71 C3.78409091,10.17 3.68181818,9.59318182 3.68181818,9 C3.68181818,8.40681818 3.78409091,7.83 3.96409091,7.29 L3.96409091,4.95818182 L0.957272727,4.95818182 C0.347727273,6.17318182 0,7.54772727 0,9 C0,10.4522727 0.347727273,11.8268182 0.957272727,13.0418182 L3.96409091,10.71 L3.96409091,10.71 Z" id="Shape" fill="#FBBC05" sketch:type="MSShapeGroup"></path>
                <path d="M9,3.57954545 C10.3213636,3.57954545 11.5077273,4.03363636 12.4404545,4.92545455 L15.0218182,2.34409091 C13.4631818,0.891818182 11.4259091,0 9,0 C5.48181818,0 2.43818182,2.01681818 0.957272727,4.95818182 L3.96409091,7.29 C4.67181818,5.16272727 6.65590909,3.57954545 9,3.57954545 L9,3.57954545 Z" id="Shape" fill="#EA4335" sketch:type="MSShapeGroup"></path>
                <path d="M0,0 L18,0 L18,18 L0,18 L0,0 Z" id="Shape" sketch:type="MSShapeGroup"></path>
            </g>
            <g id="handles_square" sketch:type="MSLayerGroup"></g>
        </g>
    </g>
</svg>

Now, update the App.js file as shown below:

import React from "react"

const App = () => {
  return (
    <div className="customBtn">
      <img src="login.svg" />
      <div className="buttonText">Sign in with Google</div>
    </div>
  )
}

export default App

Next, add the following CSS rules in the index.css file.

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

html {
  font-size: 10px;
}

.customBtn {
  margin: 10rem;
  width: 19rem;
  height: 4rem;
  background-color: #4285f4;
  border-radius: 0.2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.google {
  margin-left: -0.3rem;
}

.buttonText {
  font-size: 1.4rem;
  font-weight: bold;
  font-family: "Roboto", sans-serif;
  color: white;
  margin-right: 1.5rem;
}

And finally, add the highlighted code snippet in the index.html file.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
    <link
      href="https://fonts.googleapis.com/css?family=Roboto"
      rel="stylesheet"
      type="text/css"
    />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <meta name="theme-color" content="#000000" />
    <meta
      name="description"
      content="Web site created using create-react-app"
    />
    <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
    <title>React App</title>
  </head>
  <body>
    <noscript>You need to enable JavaScript to run this app.</noscript>
    <div id="root"></div>
  </body>
</html>

Start the development server using npm start and you should see the following result:

You can read more about the Google sign-in branding guidelines at the link here.