When using Google’s services either through its various websites:
- Gmail …
Or via the use of an Android phone, Google records data, tons of data.
To learn more about the extent of the collection, I suggest you go to Google Takeout to retrieve the data related to your Google account. You will then receive a link by email on your Gmail address. This link will allow you to retrieve a file, all you have to do is extract it to analyse what Google has about you, folder by folder.
Good luck and don’t forget that this is only what is linked to your account, so some data about you is not present.