Three kinds of data, roughly
First is what you hand over directly: your name, birthday, email or phone number, profile photo, videos, comments and messages. Second is how you behave in the app: what you watch, for how long, what you like, share, search for and skip.
Third is technical information about your device and connection, such as phone model, operating system, language, IP address and approximate location. Each app's privacy policy lists what it collects, and those details can change.
Why apps want it
Much of this data powers the feed. Watch time and skips tell the algorithm what to show you next, which is why your For You page feels so personal.
It also supports advertising, safety systems that detect spam or abuse, and product improvements. Knowing this helps you decide which trade-offs feel acceptable to you.
Phone permissions: your first line of control
Your phone decides what an app can reach: camera, microphone, photos, contacts, location and more. Open your phone's settings, find the app and switch off anything it does not need right now.
Choose "only while using" or "ask every time" for camera and microphone, and consider sharing only selected photos rather than your whole gallery when your phone offers that choice.
In-app settings worth checking
In TikTok's privacy and ads settings, look for options related to personalised ads, contact syncing and suggesting your account to people you may know. Turning off contact syncing stops the app using your phone book to make suggestions.
Some apps also offer a way to download your data. Requesting a copy is an eye-opening way to see what is stored about you.
What you cannot fully switch off
Some data is needed for an app to work at all, such as account details and basic usage. Limiting permissions reduces what is collected, but it does not make you invisible.
If privacy matters a lot to you, share less personal information in the first place, and check local data protection rules for rights such as asking a company to access or delete your data.
Frequently asked questions
Does TikTok listen through my microphone?
Apps generally need microphone permission to record, and your phone shows an indicator when the mic is in use. If you are unsure, set microphone access to only while using or ask every time.
Will turning off personalised ads stop all ads?
No. You will usually still see ads, but they will be less tailored to your activity. The setting changes how ads are chosen, not whether they appear.