Recover deleted files in Android I have deleted some files by mistake on my Android mobile, and I'd like to get them back. I tried using Dr. Fone, but it brought me A LOT of documents and images back which are not even deleted, for example it showed me icons used in Viber, icons used in Skype. It showed ALL documents even non deleted. And on top of that, when I tried to recover a document, it asked me to pay and so on. I'd like to have a free solution for this.

I tried an App called: Undeleter, but it asked me to if my device is rooted or not, and it told me that my device does not appear to be rooted. (I don't know what rooted means). What should I do? I am an absolute beginner and any hint is appreciated. 

Thanks.
There are 2 methods of recovery at the top of my head:

Making an image of the entire flash partition that contained the files and using filters to find deleted but not yet overwritten data.

For this to be successful you definitely need root access, which means to have access to the highest system privileges in Android.

You need them to access the device directly.
There are Android apps and Linux Programs (you can run those aside of android if you have root access) that do scrape the deleted files for still whole enough files automatically.

To get root access on your device I may redirect you to xda-developers.com/root wwhich has also a nice explanation what root does.

-- 

This method has less chances of success but does not require root access.

Copies of the files in question that remained in cache folders. (Often the case with images.)

Therefore just search through any folder including hidden ones for folders with words like tmp or cache, maybe there is a thumbnail version still left.

Search with a file manager, not with the gallery. Most file managers have an option to show hidden files and folders in their settings.

--

Also here is some plausible guide from Androidpit that recommends specific apps.
https://www.androidpit.com/how-to-recover-lost-data

I am not affiliated with Androidpit.
I know very well how to do a root recovery manually but can not test any apps that automate it because I dont have an android phone right now. (3310 ftw)