Hello,
First of all, thank you for your purchase.
Yes, the plugin can automatically create the meta description of posts, please check this tutorial video for details: https://www.youtube.com/watch?v=tv6fN5Hag_0
If you set up automatic editing of posts/pages/custom post types, than yes, they will be edited when they are published. You can do this in the ‘Automatic Content Editing’ tab.
If you want to edit existing content, you can do it in the ‘Existing Content Editing’ tab. To select which post type will be affected by running, please check the ‘Post Type’ settings field, where you can enter: post, page or the name of your custom post type. Tutorial on this: https://www.youtube.com/watch?v=33lB-ddmNGM
For shop categories there is a different approach, as they are taxonomies, not posts. Please check this video for details on this also: https://www.youtube.com/watch?v=k5BFo9jcmcs and also https://www.youtube.com/watch?v=kejec1aah48
Regards, Szabi – CodeRevolution.