There are various ways to cntribute to the project.
USER EXPERIENCE
Bug reports and features requests can be filed in the Issue Tracker or to the developer, see https://peazip.github.io/peazip-more.html
Please note that a quick search in the Issue Tracker database can prevent the creation of duplicate requests, and even provide solutions or workarounds.
TRANSLATIONS
PeaZip is localized in over 30 languages thanking the effort of the community in providing and maintaining the translations
Information about translation is available in PeaZip's Translation reporitory https://github.com/peazip/PeaZip-Translations and on https://peazip.github.io/peazip-translations.html page.
Translations can be sent to the developer (https://peazip.github.io/peazip-more.html for contact details) or directly committed to main PeaZip's repository https://github.com/peazip/PeaZip/tree/sources/peazip-sources/res/share (translations are in the "lang" subdirectory)
THEMES
PeaZip can be thoroughly customized in terms of icons, colors, and look&feel of the file/archive manager.
Themes page https://peazip.github.io/peazip-themes.html provides all information to start customizing the application either for personal use or for submitting themes to the community (some examples of user provided theme packages are linked in Themes page).
CODE CONTRIBUTIONS
PeaZip is mainly developed in FreePascal using the Lazarus IDE https://www.lazarus-ide.org/
If you are familiar with Pascal language family, or if you are studying one of the many Pascal dialects, you may find interesting to work on sources starting fromn https://peazip.github.io/peazip-sources.html page, in order to improve the program either for your own use or for sharing it with the community, either as a fork of the project or as a codde contribution to the project itself.
If you are not familiar nor interested in Pascal, there are other ways to contribute code to the project, especially in the system integration side, in example: creating Windows context menu entries (currently static methods are employed), creating Linux/BSD .desktop files and generally improving integration on the various DE, creating macOS services menus with Automator.
PORTING AND PACKAGE BUILDING
PeaZip aims to be a cross-platform application, and is currently available for BSD, Linux (compiled for various widget-sets and for aarch64 and x86_64 architectures), macOS (both aarch64 and Intel architectures), and Windows/ReactOS.
Lazarus/FPC can target many more combinations of architectures, Operating Systems, and widget-sets, and any help is welcome in order to port PeaZip on them.
Also, it is very welcome any help for improving existing packages (Portable, DEB, RPM, DMG, Windows installers), and for creating and/or maintaining new packages, like distribution-specific Linux installers working in accordance with repository maintainers - Debian DEB repository and Ubuntu Snap repository are two prominent examples.