I'm using Citavi to create the BibTeX file for my paper. I'd like to change the formatting for the bibliography.

Citavi has no direct influence on the formatting of the bibliography in TeX. Citavi handles the content, but not the display. Citavi exports "raw" data to a BibTeX file, which in turn is used by the BibTeX compiler to format the citations and bibliography following the rule set in the bibliography style selected in your TeX document.

Sometimes the style might need the entries in the BibTeX file to be in a certain format.  If this is the case, you can customize the BibTeX export in Citavi if necessary.

If you work with Microsoft Word or OpenOffice Writer or LibreOffice Writer, Citavi's citation styles control the formatting of citations and the bibliography. You can choose the appropriate citation style in Citavi or request it if it is the official style for a journal or publishing house.  Otherwise, you can also create your own style using Citavi's Citation Style Editor.