Package format is a type of archive containing computer programs and additional metadata needed by package managers; an instance of this type of archive is called a package. While the archive file format itself may be unchanged, package formats carry additional metadata, such as a manifest file or certain directory layouts. Packages may contain either source code or executable files.

Packages may be converted from one type to another with software such as Alien.

Packages are an important component in managing the security and integrity of the software supply chain. Packages containing executables and configuration can be digitally signed to establish the integrity of running software and protect against tampering.

Package formats that support code signing include .deb (Debian), .msi (Microsoft Windows), .apk (Android) and .ipa (IOS, IPadOS).

Arch Linux's Pacman and Slackware use 'tar' archives with generic naming but specific internal structures.