"He will report into Charles." or "He will report to Charles." ? "He will report into the Collectorate." or "He will report to the Collectorate." ?
Report to is normally used when the subject is a singular entity.
You will report to the CEO
This position reports to the board.
Report "into" can be used when describing when a person reports to a position (esp. multiple positions) in a company, rather than the person in that position:
You will be reporting into the Regional Sales Head's team, with a dotted line to the Business Unit Head.
Although generally speaking this usage is less common, and it's normally easier to just use "to".
Report into also more commonly used to describe what the report is about:
The report into the botched military operation was delivered to the President by the Joint Chiefs.
My report into the American Revolutionary War is due on Tuesday.
It is also used to show insertion of a report into some portfolio, or rendering the report into a specific format:
We posted the report into the website's "reports" section.
We saved the report into a PDF.
We added the report into our proposal.