Canned Replies
Canned or predefined replies are very useful feature for improving moderation process, or speed up responses in the support forum. Keymaster can create categorized list of replies, and those replies will be available to users of selected roles to add when writing a reply.
Canned Replies Settings
Once you enable Canned Replies, you have only few settings to look at. Most important option is to select user roles that will be allowed to use canned replies (it is not advisable to give access to canned replies to regular users).
You can also enable Categories for canned replies, and the tweak to canned replies box behavior to have it closed after content is inserted in editor. You can also change labels used for Canned Replies and Category.
Canned Replies Editing
The admin side editing is the standard post type interface, and the editor is Classic editor, it doesn’t need to use Block Editor.

Using Canned Replies
Once you have canned replies created, just above the main reply form editor, button/link Show Canned Replies List will be added. Click the link, and the box will be opened listing all canned replies.

When you click on the reply title in the list, that reply content will be added at the cursor position in the reply editor. You can add more than one reply this way into editor.