CryptoTrader.Tax only needs "Read" or "View" access to import your trade history. This permission protects your accounts. Learn more about API access in this article here.
Login to your Kraken account.
Select your profile from the top-right dropdown menu and click on API
Direct Link: https://www.kraken.com/u/security/api
Click the Add Key button and create a new API key with the settings below. After the settings are filled out, click the Generate Key button.
Be sure the following checkboxes are enabled:
Query Open Orders & Trades
Query Closed Orders & Trades
Query Ledger Entries
On the next screen, copy the API Key and API Secret values. These will be needed for later to import your transaction history.
Once copied, click Save at the bottom.
Navigate to the Kraken tab inside CryptoTrader.Tax and enter your API Key and API Secret into the the provided text boxes.
Finally click Sync Transactions to import your transaction history.