I setuped my splunk env with single indexer, search head and 10 forwarders.
Now some reason i want to change configuration in this all inputs.conf and outputs.conf file.
I saw example in splunk by creating app folder inside splunk/deplyment-app.
But i want to know can we do this from GUI ?
You can't manage indexers from the GUI. You will need to set up a deployment server (perhaps on the search head) and implement it manually.