This does not touch any sensitive parts of your phone/tablet or storage and root is not required at all. However about 25+Gb of free storage is required on your device to sync and save the cardano mainnet.
As the chain grows the storage requirment will grow as well.
Cardano-node on android
Follow these instructions to get cardano-node on your Android phone.
Install termux on you Android phone.
Open termux enter the following command:
curl https://raw.githubusercontent.com/lowskidev/cardano-android/master/setup.sh | bash
Let this run for a little bit, it will install Debian and download all th cardno node files.
When it's done you should see a message about debian launching in 10 seconds, and you will need two more commands to get everything setup and going.
Those commands are:
cd node
and
first-setup.sh
If it all goes well it should automatically start the cardano-node