To create a viewing key using Keplr Wallet, follow these steps:
Log in to your account using the Keplr Wallet Google Chrome extension.
On the top-left corner of the Keplr extension, you will see a drop-down menu with 3 horizontal stripes. Click on it.
In the drop-down menu, you will see an option to "Add Token". Click on it.
You will be prompted to input a token address. Enter your desired token address and click "Submit". You will then be prompted to approve gas fees and broadcast the transaction. This will create a viewing key for your selected token.