Message sending procedure, includingĮmail server authorization, performed by Microsoft Outlook. The same way as the native Mail Merge feature does. Mail Merge Toolkit works as a COM add-in within the desktop Microsoft Office environment, creating personalized messages to be later sent by Microsoft Outlook for Windows. And your email account has been compromised in some other way, not related to our software. We understand your concern, but we can assure you that Mail Merge Toolkit is a secure solution. * We are happy and always here to help you, and share the Microsoft 365 for business online information with you. Jennifer * Beware of scammers posting fake support numbers here. If you have any further concerns, please feel free to let me know. If so, you may use the mail merge feature in Word to send emails.
Use mail merge for bulk email, letters, labels, and envelopes
Provide a default mail merge feature, you may take a look at the following article to get the detailed instructions of this feature and check if it can meet your requirements:
However, based on my knowledge, Microsoft Word
Moreover, regarding your question “Is MAPILAB a certified Microsoft partner and how secure are their software add-ins?”, I did many researches but failed to find any related official document mentioned this. About the problem that your account got hacked, we highly recommend you immediately change your password and enable two factor authentication for your account for security concern.