How to do financial analysis with ppt?

I'm not sure what you mean by not changing PPT format.

Our company does PPT, if we don't paste excel screenshots into PPT;

Alternatively, you can select a table in excel, select Copy, and then in PPT, click Paste Special and select the worksheet object (as shown below). Then you can double-click the table in PPT and copy and paste the data directly in excel without changing the format or anything.