If your goal is the absolute smallest file size for a long report, use these settings in the 7-Zip "Add to Archive" dialog : : 7z. Compression level : Ultra.
: It treats multiple files as a single continuous block, which is highly effective if your report consists of many similar documents or revisions. good.7z
: If your report contains sensitive data, 7-Zip offers strong AES-256 encryption , which can also hide filenames within the archive. Recommended Settings for Maximum Reduction If your goal is the absolute smallest file
: LZMA2 (best for modern multi-core CPUs). 7-Zip offers strong AES-256 encryption
: Solid (this helps if you are archiving many related documents). Does 7z compress better than zip? - Microsoft Community Hub