A decentralized application is an application run by many users on a decentralized network with trustless protocols. They are designed to avoid any single point of failure. They typically have tokens to reward users for providing computing power.
Dapp.com is the platform that will guide and help you to know more about DApps. Visit https://Dapp.com and join telegram group for more information https://t.me/dapp_com. This is the future of blockchain technology, better to be first in this industry.