hrcode

The WPTelMessage plugin works with contact forms such as Contact Form 7, WPForms, and NinjaForms. 
You can also configure the WPTelMessage plugin to work with WooCommerce, allowing you to receive notifications in Telegram about orders in your store and respond to them promptly. 
 
The WPTelMessage plugin has minimal settings. All you need to do is specify your Telegram group number and the token of your Telegram bot. After that, you only need to activate the contact form from which you want to receive messages. 
If you are using the WooCommerce plugin, in addition to activating the message reception feature, you will also need to enable the necessary notifications for orders or products.
<h3>Additional Info</h3>
<h4>Resources used by the WPTelMessage plugin</h4>
The WPTelMessage plugin uses the Telegram API (https://core.telegram.org/api) for its operation. 
The token number and chat ID you specified are required for the plugin to work and will be sent to the Telegram servers. 
Messages from contact forms and the WooCommerce plugin will also be sent to the Telegram servers.
You can read the Telegram API terms of use and Telegram privacy policy here: https://telegram.org/privacy/ru

WPTelMessage

The WPTelMessage plugin will help you quickly receive messages sent from the contact form on your website or from the WooCommerce plugin in Telegram.

hauxh

This plugin allows you to require a secret key that is passed via the URL: http://example.com/post-title/?key=[string] 
Specify the key in a custom value called “key” with the [string] or use the built in widget.
Stable version of the plugin are pushed to the WordPress repository, 
but the latest version of the plugin can be found at: 
https://bitbucket.org/excion/wpkeyme/
Issues/Bugs: https://bitbucket.org/excion/wpkeyme/issues

WPKeyMe

This plugin allows you to require a secret key that is passed via the URL: http://example.com/post-title/?key=[string]

WPTelMessage vs WPKeyMe