The Smartfan allows voice control via Amazon Alexa but you first need to enable the Skill.

Amazon do provide their own guide that can be found here:

Amazon help - Skill setup

Please follow the below steps to setup the Alexa skill:

Open the Alexa app on your smart phone or device and select the menu icon top left of the screen
Select Skills and Games
Type "HomeWizard Climate" in the search bar and click on the Homewizard Climate Skill
Click on ENABLE TO USE, you will be directed to the HomeWizard Account login page.

Login with your HomeWizard details used when you first setup the Smartfan.

Once logged in please select "AUTHORISE" to allow Alexa to connect to your Smartfan,
Return to the Alexa app and click on "DISCOVER DEVICES" your Smartfan will be detected and added to Alexa.

You can now ask Alexa to "Turn on the Smartfan" or "Turn off the Smartfan".

Should you wish to rename the Smartfan you can do this under the settings page for the Smartfan device.