Depending on the way you created your address there are different things you can do and best practices to follow to backup an adderss/wallet.
If the address is in use on a node, you will for sure have the json file of the address and can follow the directions here
Each node stores data of the addresses it can work with in the keystore directory. The directory tree used in this guide is based on a self-installing Quadrans Linux node.
The unlock password.txt file is tipically stored on quadrans user home folder
The wallet private key for Mainnet nodes is available in:
The wallet private key for Testnet nodes is available in:
In those directories there is one json file for each address whose name is in the form:
is the file name of address 9acb9ff906641a434803efb474c96a83775628f7 created april 28th 2017 a few milliseconds afther 8:46 and 52 seconds
It contents might look something like:
Those files are encrypted format and can safely be copied from one node to another. You need to use the corresponding password in order to unlock and use it
In order to operate and/or migrate the account form one node to another you need to have:
the Json file
the corresponding password (password.txt for Quadrans nodes)
Save those two, back them up and store them in a safe place