WP SimplePost Contributors plugin allows you to add more than one author to the post.
Installing WP SimplePost Contributors can be done either by searching for "WP SimplePost Contributors" via the "Plugins > Add New" screen in your WordPress dashboard, or by using the following steps:
- Download the plugin via WordPress.org.
- Upload the ZIP file through the "Plugins > Add New > Upload" screen in your WordPress dashboard.
- Activate the plugin through the 'Plugins' menu in WordPress
- Visit the post page and configure, as desired.