You are looking for a Custom Meta Box.
See: https://developer.wordpress.org/plugins/metadata/custom-meta-boxes/
Once you have created and saved the meta field to the post. You can pull it out like regular post meta data.
You are looking for a Custom Meta Box.
See: https://developer.wordpress.org/plugins/metadata/custom-meta-boxes/
Once you have created and saved the meta field to the post. You can pull it out like regular post meta data.