Wikipedia
Team Win Recovery Project (TWRP), is an open-source software custom recovery image for Android-based devices. It provides a touchscreen-enabled interface which allows users to install third-party firmware and backup the current system, which are often unsupported by stock recovery images. It is, therefore, often installed when rooting Android devices.
Since February 2016, the version number convention has been modified. The first three digits specify the version, while the fourth digit, separated from the others by a dash, specifies an update for a specific device. This could be a performance improvement or a bugfix.
TWRP currently supports the installation of custom ROMs, kernels, add-ons (e.g. Gapps), and other mods.
Wiping, backing up, restoring and mounting various device partitions (e.g. system, boot, userdata, cache and internal storage) are also supported. TWRP also features file transfer via MTP, a basic file manager and a terminal emulator. It also is fully themeable.