You first need to login to WHMCS to accomplish this task.
1. Hover on “Clients” on the menu tabs at the top, and select “Mass Mail Tool“.
2. Select the email type. You can send a “General” email or an email concerning a “Product/Service” or an email concerning an “Addon” or an email concerning a “Domain“.
3. Select the client criteria. It could be that you are sending an email to a specific client group or clients from a certain country or clients with a particular status such as “Inactive”.
4. Select other criteria related to the email type. For instance, if you chose “Product/Service” in step 2, you have to select the products and their status to determine which clients and which not, to send to.
5. Compose your message.
Please Note: You can attach files at the bottom of that page and also there are available merge fields to include in your email if you would like to personalize the message with client-specific parameters
6. Send your message.