docs: PAT setup added to readme

README.md

@@ -43,6 +43,20 @@ module.exports = nextConfig
 
 ## Usage
 
+Clarifai uses **Personal Access Tokens(PATs)** to validate requests. You can create and manage PATs under your Clarifai account security settings.
+
+* 🔗 [Create PAT:](https://docs.clarifai.com/clarifai-basics/authentication/personal-access-tokens/) ***Log into Portal → Profile Icon → Security Settings → Create Personal Access Token → Set the scopes → Confirm***
+
+Export your PAT as an environment variable. Then, import and initialize the API Client.
+
+Set PAT as environment variable through terminal:
+
+```cmd
+export CLARIFAI_PAT={your personal access token}
+```
+
+or use [dotenv](https://www.npmjs.com/package/dotenv) to load environment variables via a `.env` file
+
 ### Using Models
 
 Using the celebrity face recognition model to predict the celebrity in a given picture. For list of all available models visit [clarifai models page](https://clarifai.com/explore/models).