Bulk Emails are used when you want to send a mass email to contacts, whether you're selecting contacts from a list or you're using filters to see the contacts you want. When sending bulk emails they work similar in the way our campaigns work, in that you are able to send hundreds of emails at a time with your name and email attached but they are sent out from our sending servers at Sendgrid, not your Microsoft 365 or Gmail account, as they do not allow for mass sending the way an email marketing server (like Sengrid) does. These emails will show under the contact profile as a follow up email activity similar to that of a One-To-One Email.
Since you are using a Sengrid server to send bulk emails, these emails will not show up in your email's sent folder (for Microsoft 365 or Gmail).
To learn more about how to send Bulk Emails check out this article: Bulk Email
NOTE: Bulk emails are typically used for sales follow up purposes, not marketing purposes. For this reason, we recommend not sending more that 100 bulk emails at one time. Marketing emails are typically sent through campaigns. To learn more about email campaigns, check out either of these articles: Graphical Campaigns or Non-graphical campaigns
One-To-One Emails are used more specifically when you want to communicate with an individual contact. The process of creating the emails itself is exactly the same as when doing Bulk Emails, but you're only directing this email to one contact vs multiple contacts you've selected. While these emails originate from inside of GlassHive they are actually sent though our email integration with Microsoft 365 which you can learn more about here: Microsoft 365 Integration.
Any emails sent from inside of GlassHive can be tracked and logged under the contact's profile, as well as the ability to track any links that were clicked.
Since these emails are being sent using your Microsoft 365 account, the emails will show in your email's sent folder.
You can learn more about how to send One-To-One emails here: One-To-One Emails