To generate the signature key, go to your Authorize.net Merchant account.
Step 1: Go to Account Settings (on the top-right hand side of your merchant account)
Step 2: Click on API Credentials and Keys
Step 3: At the bottom of the page, you'll see an option to obtain a new signature key. Select this, and disable the old one if it is not being used elsewhere. Hit Submit. You'll be requested to verify your identity using a PIN. Validate this.
Step 4: Once you complete the validation, you will be redirected to a screen that displays the current signature key. Copy this to your clipboard.
Step 5: Proceed from Step 4 on this article or
if you already have an Authorize.net account already created on Almabase and you just need to update the signature key then Email this key to your Account manager and CC: firstname.lastname@example.org.
We'll update this on our end and let you know.