- Click on My Office
2. Click on Settings
3. Click on Payment Gateway Settings.
4. Click on Add New
5. Select Authorize.net in the drop down.
6. Enter your API Login ID. (Provided via e-mail from Authorize.net)
7. Enter your Transaction Key (Provided via e-mail from Authorize.net)
8. Change Set As Default to Yes.
9. Click on Save.