An advertising ID lets apps and developers know which app is advertised, and show that advertiser’s other ads. For example, an e-book reader may want to carry ads from a newspaper (that is, the newspaper would like its own ad displayed along with the book). But since the newspaper has already shown you its own ads, it can’t keep track of them with the same ID. Instead, it needs its own separate advertising ID so that when you click on their ad in the book or magazine, they can know that they’ve already shown you an ad and not bother showing you another one later on.

What is an advertising id?
How to find IDFA on iPhone?
For iOS Devices, including iPhone, iPad, and iPod touch, at present, the advertising ID on iOS devices is hidden from users by Apple by default.
To find out if you have an IDFA on your iOS device, please follow the steps below.
1. Go to Settings > General > About
2. Scroll down and look for advertising and tap on it to see if it says “IDFA”.

How to find Android Advertising ID?
Open your Apps or App Drawer and go to Google Settings. In Google Play Services, scroll down and tap on ” Advertising ID “.
Why does Google need this information?

The advertising identifier does not provide personal information to the apps you use. Google only uses it to provide targeted ads, based on factors such as your interests and other activity on Google services.
To do this, Google needs to know which ads you’ve seen so that if the same ad appears again, it knows not to show that ad to you again. Google can then also group your past behavior to give you more relevant ads across all your devices. If an app developer shares information with other parties outside of Google, including straight-up selling it, they’re in violation of Google’s policies.
What happens if I don’t provide my advertising ID?
You won’t be able to install or sign in to apps, and you may see a less personalized experience on Google services.
Apps that use identifiers for advertising with ad networks still have the option of showing ads even if they don’t know your identifier. However, those ads might not be as relevant to you as they could otherwise be.
For example, when you watch a movie on Google Play Movies, an app may use your advertising ID to show you ads for films in the same genre. However, if you never provided your advertising ID to that app, it might not be able to show this ad.
Google is very careful about keeping your information secure. The company uses technical and organizational measures to protect all of the data you share with Google.
You can find out more specific details about how Google treats advertising IDs in Google’s Privacy Policy .
What if I don’t want my identifier collected by Google?
You can turn off the android advertising identifier in your device’s settings. You may also be able to opt out of certain publishers’ use of this information.
Advertising identifiers for other devices
If you’re using an iOS device, visit Apple’s About Advertising Privacy page for more information about limiting ad tracking or resetting the IDFA on your device. And for more information about how to limit ad tracking on your iOS device, visit Apple’s About Advertising Privacy page
If you’re using an older version of Android, then you’ll need to select or reset the advertising ID value. You can do this through your Settings app by going to Applications > Application manager and scrolling down to find the “Advertising” app, then selecting it and choosing “Reset advertising ID” option.
How do I delete or edit my ad preferences and marketing settings?
You can edit or delete your ad settings in your Google Account. Learn how to change or remove recent activity that helps choose which ads you see.
To manage your ad preferences and marketing settings, you can also visit your Google Account. You can edit or delete activity that might have been used to choose which ads you see.
If you want to delete specific ids from a site, for example an app or a TV show website where id is collected, then go to My Activity page on Google, find the item in question and click on “Activity Controls” link. At the bottom, you will see a checkbox labeled “Limit Ad tracking”. Check that box and save changes.
On android phone, under Google Settings, you have a switch to turn ad personalization off/on if I no longer want your preferences tracked by Google.
Is my identifier reset after I reset my device or factory-reset an app?
Yes, you will need to select a new identifier after a factory-reset.
Targeting devices without an advertising ID?
Some apps and services may use a randomly generated number instead of an advertising ID to help remember your settings or provide similar personalization. Google’s Privacy Policy does not cover this identifier, so check the app’s privacy policy or contact their support team for details.
What if I don’t want Google to use my identifier for personalizing ads?
You can opt out of personalized ads:
If you have an Android device, open your device Settings and select Google > Ads Please note that even if you opt out, you may still see non-personalized ads.
On iOS devices, go to the Settings of your device and select Google > Limit Ad Tracking Please note that even if you opt out, you may still see non-personalized ads.
How can I find out more about the privacy settings for my device?
You can visit your Privacy Checkup to review what Google knows about you and how it’s used, as well as edit your settings.
How does Google use this identifier?
The primary goal of this identifier is to remember things like:
Purchases you’ve made on Play Store apps so we can recommend related content in the future,
Which apps you’ve installed through Google Play app listings so we can recommend similar apps or tell you about new updates,
Settings in Android apps when you change them so they’ll open at the right time when you use them next.
Customizations like your theme colors in Chrome so websites will look how you want them to.
ARTICLE END
If you have any additional questions, feel free to leave a comment below the article.
Note: You can find more information on privacy and your Google Account here .
On android phone, under Google Settings, you have a switch to turn ad personalization off/on if I no longer want your preferences tracked by Google.
Note: This article contains information about deleting or editing your recent activity, ad settings in your Google Account, and what is my identifier on android devices.