Agile is not only in software development, rather it is also used retail, strategy-building, human resources, auditing, budgeting, manufacturing and even organizational culture. The reason Agile rose to prominence was that it was the answer to rapidly changing shifts in the marketplace. It allowed manufacturers to constantly make changes in the product as the expectations of customers were evolving with time and technology.
While initially it was only used to manage a small team, in a few years it was used to manage multiple teams and then later the entire organization. The most popular methodology of Agile, Scrum took the front in the years to come. Scrum allows teams to self-organize themselves, with a team lead managing them.
Over time, Agile methodologies evolved and new methodologies were listed under its vast umbrella. Managers who were efficiently using Agile understood that it is more than a methodology, that Agile is actually a mindset. Currently, several organizations in the world use a derivation of Agile that they have created after years of experimentation.
Some of the largest companies in the world like Amazon, Facebook, Google, Microsoft, Netflix use Agile in achieving their day-to-day and overall objectives. Because of their business agility, they have climbed up the ladders of success.