It is no surprise that Facebook stores an enormous amount of data about you. Some of that information comes directly from other companies that you communicate with online. Here's how to see which companies upload your off-Facebook activity to the social network.
What is Off-Facebook activity?
Off-Facebook activity is information that companies and organizations share with Facebook about interactions that you have with their apps and websites. Companies that use Facebook's Business Tools, such as Facebook Login or Facebook Pixel, share this information with the social network about how and when you use their websites.
Examples of interactions are:
- An app opened
- Logged in an app with Facebook
- Visited a website
- Search for an item
- Added an item to a wish list
- a shopping cart
- Made a purchase
- Made a donation
Companies use the information they collect to tailor a more personalized Facebook experience for you. Activity is used to show you more relevant ads, to recommend groups, events or Marketplace items, to discover new companies and brands, to help companies understand how the website, app or ads are performing, and to identify suspicious activity.
RELATED: How to see which Facebook advertisers have your private data
Sometimes you see activity in your off-Facebook activity that you do not recognize. That's because it may have been sent through an external data service provider or marketing agency hired to analyze the interactions of a company on its apps and websites.
Also, activity outside of Facebook does not mention all details. Facebook receives much more information – but for technical and accuracy reasons – it does not show everything. This includes information obtained when you are not logged in to Facebook or when they cannot confirm that you have used Facebook on a particular device. Items added to your shopping carts will not appear in your activity.
Facebook prohibits the uploading of sensitive information, including health and financial information, date of birth and passwords. The company also declares that it does not sell this information to anyone.
How to see which companies upload your data to Facebook
Now that we know what kind of information is uploaded and stored, we look at how you can see which companies send data about you and your habits to Facebook.
Start your browser, type
https://www.facebook.com/off_facebook_activity/ in the address bar and then press Enter.
For security reasons, you must enter your password again when the prompt appears. 
When the page loads, you will see the heading "Activity outside of Facebook" with an example of some of the apps or websites that have recently uploaded data about you on Facebook. Click on an icon to open the entire activity list.
On the next page, Facebook shows a list of every app and website that your activities have shared.
Click on an activity to view more details.
Because it takes a few days for all activity to appear in your off-Facebook activity, you may not see everything that has been uploaded. The dates in the activity overview are listed when they have received the information.
Here you can see how the app or website has shared your information and how many interactions have been received.
If you click on one of the activity details, you will get more information about the service itself, but you cannot see exactly what has been shared.
Disable future activity sharing on Facebook
If you no longer want an app or website to synchronize with your Facebook account, you must be able to manage future activity of specific apps and websites.
Open your browser, go to your off-Facebook activity list, log in to your account and then click on an app or website on which you want to manage future activity. 
Scroll down to the bottom of the list and click on the "Turn off future activity from" option.
Disabling future activities can affect the functionality of an app or website that you use regularly, so read the warnings before selecting the "Disable" button.
Disabling future activity does not remove post activity; it only hides it and prevents everything that is received from now on from being displayed in your activity list outside of Facebook. Click on "Close" to ignore the message. We will discuss later how you can delete your history.
Download your information from Facebook
As mentioned earlier, you cannot view every interaction in the activity list of every app or website. For that you have to download your information and view each item to see a slightly more detailed overview of all your interactions.
RELATED: Ever wondered how much Facebook knows about you? Here's how to see
Start your web browser and go to the Your Facebook Information page. Click on "Download your information" after logging in to your account.
Then click on "Deselect all" to uncheck all available options if you only want the off-Facebook activity list. .
Scroll down at the bottom and check the box next to "Advertisements and companies."
at the top choose the date range, file format and quality of the media and then click on the "Create file" button.
Enter your password when the prompt appears. You will be informed that it takes a few minutes for Facebook to prepare your data. It took us about five minutes, which in the end was less than 1 MB. Facebook will notify you when the file is ready for download.
When the file is ready, click on the "Available copies" tab and then select the "Download" button next to the file.
The file is downloaded to where your browser saves files and has the ZIP file format.
RELATED: Everything you need to know about zip files
Manage your off-Facebook activity
If you have accidentally removed an app or website from your activity list or If you want to completely disable the off-Facebook activity list, we'll show you how to do both.
Start up your browser and go to your off-Facebook activity list. Log in to your account and then click on "Manage your off-Facebook activity" on the right-hand side of the page.
Click on the "Manage Future Activity" button.
To completely disable this function, set the switch next to "Future off-Facebook Activity" to the off position.
A dialog box appears with a list of some things that you should take into account when disabling this function. Read through the list to make sure that this is the right decision for you. Click on the "Disable" button to confirm your action. Select "Cancel" to go back to Facebook.
Disabling future activities does not prevent companies and organizations from sending information about your activity apps and websites to Facebook. The data is disconnected from your account, but Facebook still uses it for their advertising systems.
To see a list of all apps and websites for which you have disabled activity, click on the "Activity for which you have enabled Off" tile.
Select the app or website that you want to manage.
Click "Allow activity from … to stay connected with your account "to re-enable activity.
After allowing activity again, you will begin to see your actions in that app or website that appears on the activity list page.
Delete your activity history from Facebook
If you want to delete your off-Facebook activity history, this is a simple process that you can complete in one few clicks. Keep in mind that if you erase your activity history, some apps and websites will log you out if you use them to "Log in with Facebook".
Start up your browser and go to your off-Facebook activity list. Click "Delete History" on the right side of the page after logging in to your account.
Read the details in the pop-up window, and then select the "Clear History" button if you are sure you want to delete your off-Facebook activity. 
Although the off-Facebook activities are an excellent way for Facebook to target ads, make suggestions for groups, events and Marketplace, it's not for everyone, luckily, if you don't these things, it is easy to manage or disable this function.