You can divide it into two groups, data sources and analytics to display it.
The sources are the central platforms, which depend on supply and demand. Therefore, the liquidity lists, buy/sell orders are what determines the price. Therefore, you will find that each platform has a different price for Bitcoin, and the price is often close because the market is open and the liquidity will shift from the platforms that have a higher price to lower price or in other words arbitrage trading
[1]As for the display tools, they obtain data through APIs for the central platforms, and thus give an
average that reflects a measure of the actual value of Bitcoin at that moment, from which you will find that the price of Bitcoin is different in CMC than cryptowatch.
The only difference between the analysis/price tracking platforms is how this average is calculated.
[1]
Arbitrage is trading that exploits the tiny differences in price between identical assets in two or more markets.
Source --->
https://www.investopedia.com/terms/a/arbitrage.asp#:~:text=Arbitrage%20is%20trading%20that%20exploits,difference%20between%20the%20two%20prices.