if a guy who going to take Data Analysis as career and wanted to know how this data analysis working on real company?

I have a doubt about where the data actually comes from and how it is stored and processed. Where is the data usually stored, and what tools do we use to connect to it for reading and writing SQL queries? For example, I assume we create a corresponding SQL view for each KPI and then connect those views to Power BI. Is this how the process generally works? Also, what other tools and techniques are commonly used to connect to data for analysis? In a real company, do you typically receive KPI requirements or tasks from a Senior Data Analyst/Data Lead, write the required SQL queries, and then deli