Add the comment notify module.

composer.json

@@ -17,6 +17,7 @@
         "drupal/block_theme_sync": "^1.0@alpha",
         "drupal/ckeditor_markdown": "^1.1",
         "drupal/coffee": "1.x-dev",
+        "drupal/comment_notify": "dev-1.x",
         "drupal/core": "^8.6.2",
         "drupal/customerror": "1.x-dev",
         "drupal/diff": "^1.0@RC",
@@ -97,6 +98,10 @@
 	    },
 	    "drupal/honeypot": {
 		"Accessibility Issue Triggered": "https://www.drupal.org/files/issues/2018-08-05/honeypot-aria-hidden-on-text-field-2944843-12.patch"
+	    },
+      "drupal/comment_notify": {
+        "Invalid placeholder (!types) in string": "https://www.drupal.org/files/issues/2019-01-16/2938134-4.patch",
+        "The unsubscribe option is not working": "https://www.drupal.org/files/issues/2019-01-17/3026687-2.patch"
       }
 	}
     },

config/sync/comment_notify.settings.yml

@@ -0,0 +1,17 @@
+node_types:
+  - blog
+available_alerts:
+  1: true
+  2: false
+enable_default:
+  watcher: '1'
+  entity_author: true
+mail_templates:
+  watcher:
+    subject: '[site:name] :: new comment on [node:title]'
+    body: "Hi [comment-subscribed:author],\r\n\r\n[comment:author] has commented on: \"[node:title]\"\r\n\r\n----\r\n[comment:title]\r\n[comment:body]\r\n----\r\n\r\nYou can view the comment at the following url\r\n[comment:url]\r\n\r\nYou can stop receiving emails when someone replies to this post,\r\nby going to [comment-subscribed:unsubscribe-url]\r\n\r\nYou can set up auto-following feature for all future posts\r\nby creating your own user with a few clicks here [site:login-url]\r\n\r\n-- [site:name] team\r\n[site:url]\r\n"
+  entity_author:
+    subject: '[site:name] :: new comment for your post'
+    body: "Hi [node:author],\r\n\r\nYou have received a comment on: \"[node:title]\"\r\n\r\n----\r\n[comment:title]\r\n[comment:body]\r\n----\r\n\r\nYou can view the comment at the following url\r\n[comment:url]\r\n\r\nYou will receive emails like this for all replies to your posts. You can\r\ndisable this by logging in and changing the settings on your user account at\r\n[node:author:edit-url].\r\n\r\n-- [site:name] team\r\n[site:url]\r\n"
+_core:
+  default_config_hash: Q6HMOSKUhb-YgBPZ1JIbcVeOxHPv-eJoBGYmXiG9Pik

config/sync/config_snapshot.snapshot.config_sync.module.comment_notify.yml

@@ -0,0 +1,30 @@
+uuid: 49585043-4c03-4f31-a704-0cc843abf295
+langcode: en
+status: true
+dependencies:
+  module:
+    - comment_notify
+id: config_sync.module.comment_notify
+snapshotSet: config_sync
+extensionType: module
+extensionName: comment_notify
+items:
+  -
+    collection: ''
+    name: comment_notify.settings
+    data:
+      node_types:
+        - article
+      available_alerts:
+        1: true
+        2: true
+      enable_default:
+        watcher: none
+        entity_author: false
+      mail_templates:
+        watcher:
+          subject: '[site:name] :: new comment on [node:title]'
+          body: "Hi [comment-subscribed:author],\n\n[comment:author] has commented on: \"[node:title]\"\n\n----\n[comment:title]\n[comment:body]\n----\n\nYou can view the comment at the following url\n[comment:url]\n\nYou can stop receiving emails when someone replies to this post,\nby going to [comment-subscribed:unsubscribe-url]\n\nYou can set up auto-following feature for all future posts\nby creating your own user with a few clicks here [site:login-url]\n\n-- [site:name] team\n[site:url]\n"
+        entity_author:
+          subject: '[site:name] :: new comment for your post'
+          body: "Hi [node:author],\n\nYou have received a comment on: \"[node:title]\"\n\n----\n[comment:title]\n[comment:body]\n----\n\nYou can view the comment at the following url\n[comment:url]\n\nYou will receive emails like this for all replies to your posts. You can\ndisable this by logging in and changing the settings on your user account at\n[node:author:edit-url].\n\n-- [site:name] team\n[site:url]\n"

config/sync/core.extension.yml

@@ -141,6 +141,7 @@ module:
   ds: 1
   menu_link_content: 1
   pathauto: 1
+  comment_notify: 10
   content_translation: 10
   indieweb_microformat: 10
   views: 10

config/sync/language/es/field.field.block_content.basic.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.action.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.article.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.blog.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.campaign.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.case_study.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.event.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.page.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/language/es/field.field.node.resource.body.yml

@@ -0,0 +1 @@
+label: Cuerpo

config/sync/user.role.anonymous.yml

@@ -14,6 +14,7 @@ permissions:
   - 'access content'
   - 'access site-wide contact form'
   - 'post comments'
+  - 'subscribe to comments'
   - 'use exclude node title'
   - 'use text format minimalhtml'
   - 'use text format restricted_html'

config/sync/user.role.authenticated.yml

@@ -19,6 +19,7 @@ permissions:
   - 'edit own comments'
   - 'post comments'
   - 'skip comment approval'
+  - 'subscribe to comments'
   - 'use exclude node title'
   - 'use text format basic_html'
   - 'use text format minimalhtml'