Everyone's idea of marketing is different. Each textbook defines it differently, and each professional will include different aspects of marketing. Marketing is a lot of things.
Merriam-Webster defines marketing as:
1 a: the act or process of selling or purchasing in a market b: the process or technique of promoting, selling, and distributing a product or service
2: an aggregate of functions involved in moving goods from producer to consumer.
This definition could not be any more general, but that in itself is the point: marketing is anything used to promote, sell, or distribute a product or service. Marketing can be passing out flyers to promote. Marketing can be the way you complete a sell. Marketing can also be who will sell your products. Marketing must be an integrated process that combines a wide variety of activities to promote, sell and distribute your products or services.
Marketing starts with determining a want or need. You must identify a reason for your product or service in order to have something to sell. Once you determine the want or need, you must create or establish the product or service that will satisfy that need or desire. Although this sounds like the beginnings of a business plan, it is also the basis for your entire marketing plan.
There are many steps to marketing once you have established a product or service that satisfies and want or need. You must make decisions about your marketing mix (product, price, place (distribution), and promotion), and you must incorporate your marketing contractual with every step. You also must combine your sales strategies with your marketing strategies to design a successful business model.
Marketing is a lot of things, but absolutely, it is any technique or process of promoting, selling, and distributing your products or services.