1. Download the 2Checkout payment module at https://github.com/craigchristenson/2checkout-wp-invoice
2. Upload the files to your WP-Invoice directory on your web server.
3. Under Invoice -> Settings, select 2Checkout for Default Payment Method.
4. Enter your 2Checkout Seller ID. (2Checkout Account Number)
5. Enter your 2Checkout Secret Word. (Must be the same value entered on your 2Checkout Site Management page.)
6. For demo sales set Demo Mode to Yes. For live sales keep Demo Mode at No.
7. Copy the URL provided under "2Checkout Approved URL/INS URL".
8. Click Save All Settings.

1. Sign in to your 2Checkout account.
2. Click the Account tab and Site Management subcategory.
3. Under Direct Return select Header Redirect or Given links back to my website.
4. Enter your Secret Word.(Must be the same value entered in your WP-Invoice admin.)
5. Paste the URL you copied from the "2Checkout Approved URL/INS URL" field in the Approved URL field.
6. Click Save Changes.
7. Under the Notification tab, paste the URL you copied from the "2Checkout Approved URL/INS URL" field in the Global URL field and enable all messages.
8. Click Save Changes.

Please feel free to contact 2Checkout directly with any integration questions.