How can a business continue to operate without making a profit?

Longtime lurker and first-time poster here. Feel free to redirect me to another subreddit or to a previous post answering this question.

I remember hearing at one point that Amazon only turned a profit after operating for about twenty years or so. I am curious how this is possible.

Is it due to accounting practices and tax incentives? Does this apply to both businesses large and small? Would the absence of a profit not allow for the business to grow or sustain itself?