[Smart Hashing] Add smart hashing documentation in readme

README.md

@@ -960,6 +960,50 @@ There are a few subtle differences from the Fetch API which are meant to limit t
 - some options and behaviors are not applicable to Node.js and will be ignored by `node-fetch`. See this list of [known differences](https://github.com/node-fetch/node-fetch/blob/1780f5ae89107ded4f232f43219ab0e548b0647c/docs/v2-LIMITS.md).
 - `method` will automatically get upcased for consistency.
 
+## Automatic Hashing Detection with `processHashing`
+
+Our popular segment Adtect destinations support [automatic hash detection](https://segment.com/docs/connections/destinations/#hashing) of personally identifyable information (PII). If your destination hashes PII data, we recommend you use the `processHashing` utility instead of `createHash` from `crypto` module.
+This utility automatically detects if a value is already hashed. It will only apply a hash if the value appears to be unhashed.
+
+The `processHashing` utility supports `md5`, `sha1`,`sha224`,`sha256`,`sha384` and`sha512` hashing algorithms. It can output digests in `hex` or `base64` format.
+
+**Note**: For empty or whitespace-only strings, the `processHashing` outputs an empty string instead of throwing an error like `createHash` hash module.
+
+### Example 1: Hashing an Email Address
+
+```
+  import { processHashing } from 'destination-actions/lib/hashing-utils'
+
+  const email = ' [email protected] '
+  const hashedEmail = processHashing(
+    email,
+    'sha256',
+    'hex',
+    (value) => value.trim().toLowerCase()
+  )
+
+  console.log(hashedEmail) // hashed string
+```
+
+### Example 2: Hashing a Phone Number
+
+```
+  const phone = '+1(706)-767-5127'
+  const normalizePhone = (value: string) => value.replace(/[^0-9]/g, '')
+
+  const hashedPhone = processHashing(
+    phone,
+    'sha256',
+    'hex',
+    normalizePhone
+  )
+
+  console.log(hashedPhone) // hashed string
+```
+
+**Requesting Additional Algorithms**
+To request additional hash algorithms, contact [email protected].
+
 ## Support
 
 For any issues, please contact our support team at [email protected].
@@ -991,3 +1035,7 @@ SOFTWARE.
 ## Contributing
 
 All third party contributors acknowledge that any contributions they provide will be made under the same open source license that the open source project is provided under.
+
+```
+
+```