If you want to password protect some of your files, that’s sharable, the most intuitive choice is to have a password protected zip

Zip vs 7z

The 7z format is a compressed archive file format, similar to ZIP, created by the 7-Zip program
It is known for its high compression ratio, strong AES-256 encryption, and open architecture, which allows it to support a variety of compression methods like LZMA, LZMA2, and BZip2
While it offers superior compression compared to standard ZIP, it requires third-party software to open, as it lacks the universal compatibility of the ZIP format

Using 7z in Android

ZArchiver

Termux

pkg update
pkg install p7zip
 
# Create (or append to) a password-protected 7z archive
7z a -pYOUR_PASSWORD archive.7z file_or_folder
 
# Extract a 7z archive
7z x archive.7z