docs: Improve clarity of "Loading and configuring" (#1323)

* docs: Improve clarity of "Loading and configuring"

* Update README.md

Co-authored-by: Linus Unnebäck <linus@folkdatorn.se>

Co-authored-by: Linus Unnebäck <linus@folkdatorn.se>

README.md

@@ -111,22 +111,22 @@ npm install node-fetch
 
 ## Loading and configuring the module
 
+### ES Modules (ESM)
+
 ```js
 import fetch from 'node-fetch';
 ```
 
-If you want to patch the global object in node:
+### CommonJS
 
-```js
-import fetch from 'node-fetch';
+`node-fetch` from v3 is an ESM-only module - you are not able to import it with `require()`. 
 
-if (!globalThis.fetch) {
-	globalThis.fetch = fetch;
-}
+If you cannot switch to ESM, please use v2 which remains compatible with CommonJS. Critical bug fixes will continue to be published for v2.
+
+```sh
+npm install node-fetch@2
 ```
 
-`node-fetch` is an ESM-only module - you are not able to import it with `require`. We recommend you stay on v2 which is built with CommonJS unless you use ESM yourself. We will continue to publish critical bug fixes for it.
-
 Alternatively, you can use the async `import()` function from CommonJS to load `node-fetch` asynchronously:
 
 ```js
@@ -134,6 +134,27 @@ Alternatively, you can use the async `import()` function from CommonJS to load `
 const fetch = (...args) => import('node-fetch').then(({default: fetch}) => fetch(...args));
 ```
 
+### Providing global access
+
+To use `fetch()` without importing it, you can patch the `global` object in node:
+
+```js
+// fetch-polyfill.js
+import fetch from 'node-fetch';
+
+if (!globalThis.fetch) {
+    globalThis.fetch = fetch;
+    globalThis.Headers = Headers;
+    globalThis.Request = Request;
+    globalThis.Response = Response;
+}
+
+// index.js
+import './fetch-polyfill'
+
+// ...
+```
+
 ## Upgrading
 
 Using an old version of node-fetch? Check out the following files: