How does my money into an ETF (e.g. VOO) get distributed?

Sorry if this is a very beginner question.

When I invest into VOO, my understanding is that my investment is getting distributed amongst the S&P500 companies (I would assume weighted according to their value).

The “top 500” companies changes over time, so I'm wondering how that effects an investment into the VOO.

For example, if the next Microsoft shows up and becomes a top 500 company, but I invested in the VOO prior to this, do I reap the benefit of the new company?

Thanks for any help 🙂

Edit:
Is the money that I've invested always in a state of flux and getting weighted into each company based on the proportion of the S&P500 that it makes up?