You can replace the author listed in Kapost with an existing author in your Drupal or Wordpress CMS. This is how you do it:
Go to account settings then to Custom Fields:
Here you want to create a new custom field. You can make the display name whatever you desire, but the field name must be:
For best results, make it a Multiple Select field type, and add your non-kapost authors in the format you see below:
Once you create a custom field you must assign this to a Content Type. To do so, simply go to Content Types and Workflow under settings, select the correct content type, select the custom field you would like to add and click Save.
When you want to publish the post you must make the value of your newly created custom field the email address (of an already existing user in your CMS). This will change the author of the post. In the image below you will see that the post is assigned to Michael, but we are sending it over so the author is listed as Tara (firstname.lastname@example.org). Once it is published the author will be changed to be Tara.
If you have all permissions checked in your Kapost Wordpress plugin, this field should sync over the author's picture and bio as well.
If it does not, please check your Wordpress instance and make sure the user email in WP matches what you've added in the Kapost author custom field you just built.
Note: This field will only sync over the author's email address (without the name) if you are using Drupal.
You also have the ability to send over the Author's Bio information from Kapost to Wordpress through the Wordpress Plugin. Learn how to install the plugin and configure this in the linked article.