Templating feature allows for creating templates which essentially are email messages stored for later use. If you need to send similar mail messages from time to time, you can mark specific folders of your email account to be used for storing templates, save emails as templates there, and use them in the future.
This functionality is disabled by default, you can enable it by setting AllowTemplateFolders to true in
"Allows for setting a folder as template one under Manage Folders screen"
After that, in Manage Folders screen, you can setup one or several folders to be used for templating.
Once you have at least one template folder, you can move mails into it. Another way to create a template is from New Message screen - open a mail from Drafts, or simply start writing a new mail.
In addition to Save button which stores mail in Drafts, there's also Save Template button. Upon editing a message, click Save Template to store message in template folder.
Any message in template folder opens for editing when you click it, so you can open a template, edit it, send a message out - but the template itself won't be changed unless you click Save Template. And if you save template more than once while editing a message, the template will be overwritten. Note that, unlike drafts, templates are not overwritten automatically.
In version 8.5.2, a new templating feature was added. Instead of creating a new message from template, you can click Template button in message editor toolbar, select a template from dropdown menu - and it will be inserted into cursor position. That way, you can use templates for replies and forwards rather than for just the new messages.
It is assumed that core templating functionality is enabled as shown above. Inline templating uses the same template folder, and message subject is used as a template name in dropdown. The toolbar button becomes visible once templates are loaded in.
This feature is disabled by default, you can enable it by setting AllowInsertTemplateOnCompose to true in
"If true, a tool for inserting a template is added on message compose screen"
If template folder contains a large number of messages, the list will be trimmed per MaxTemplatesCountOnCompose setting found in the same configuration file, defaults to 100.