This article helps you learn more about how add-ins work..
Why do I see Outlook add-ins in my inbox?
Microsoft has partnered with leading companies to build add-ins that help you get things done right from your inbox. Add-ins in Outlook.com or Outlook on the web are programs or utilities that help you automate tasks when you view or create messages.
How do the add-ins work?
Pre-installed add-ins are enabled by default, but users must still give consent before these add-ins can access the user's data. Even after you activate them, they can only run when you tap or click the add-in. Most add-ins have access only to the data in the email message that you're working in.
When you install an add-in in Outlook.com or Outlook on the web, it will appear in other versions of Outlook as well. For example, if you install an add-in in Outlook on the web, you will see the add-in when you open Outlook 2016.
All add-ins are validated by Microsoft, including those that you install from the Office Store. For more information, see the privacy statement and the terms and conditions section in the add-in’s consent form.
To learn how to use the add-ins, see Using Add-ins in Outlook on the web.
How do I enable or disable add-ins?
Select Settings > Manage add-ins.
For free add-ins, use the toggle controls to turn them on or off. For paid add-ins and free trials, select Get it to finish your purchase.
You can also install more add-ins from the Office Store.
How do contextual add-ins work?
Outlook detects if add-in requested keywords or entities, such as meeting suggestions or addresses, are in your message, and it underlines them. Please note that Microsoft always safeguards your privacy and doesn't attempt to read or comprehend your message. Even though you might see underlined text, no information is sent to the add-in.
Remember, the add-in can run only after you have given your consent to activate it and you selected the underlined text.
Does the add-in send my data to third-party service? If so, why?
An add-in might send data to its own service, but only to complete the task you've requested. For example, the Bing maps add-in might send information to the Bing online service in order to find the location you've requested. All add-ins are required to comply by their privacy policies and Microsoft standards. See the add-in privacy statement for more details.
Where can I get more information about an add-in, its ratings, and reviews?
Go to the Office Store, and search for the add-in you're looking for. Then, select the add-in to find information such as its overview, requirements, ratings, and reviews.