Agile software development is introduced to overcome challenges facing by traditional software development life cycle. Any software development life cycle uses the 4 values and 12 principles specified in the agile manifesto is implementing agile. There are a few agile frameworks like Scrum, Kanban, XP(Extreme programming) to implement agile.
The main common objective of agile frameworks like Scrum, XP or Kanban is to be able to change the process after starting the product according to requirements. All agile frameworks follow the incremental approach and project details can be changed during the software development cycle.
If you want to learn about Agile methodology and frameworks, you can take up the Agile Training course by intellipaat.
You can watch this video on Agile methodology for detailed explanation: