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Reason: Additional information on the processes to be added following changes to Translation Team structures in 2021.
What is Crowdin?
Crowdin is a cloud-based solution that streamlines localization management for your team. It's the perfect place to effectively manage all of your multilingual content.
The Joomla CMS official language packs and many other aspects of the project are managed using Crowdin to facilitate managing L10n activities.
Create an account
To start using Crowdin, create an account at https://crowdin.com.
Once you've created your account, visit the Crowdin Project for Joomla to contribute to the core language packs for the project, or joomla.crowdin.com to contribute to other language packs for Joomla websites, Joomla marketing projects and other Joomla extensions.
The core language packs for Joomla will be migrated soon into joomla.crowdin.com to have all of the content in the single channel.
You'll also find a number of other Joomla components who are using joomla.crowdin.com for their translations management, so you can assist with translating them too.
Joomla Documentation doesn't use Crowdin for translation as it's built into the wiki. See the Documentation Translation Quickstart guide for more information.
Joomla Translation Teams
The also has a range of documentation articles that translators can contribute to.
Crowdin have a comprehensive Knowledge Base which new users would be well served to familiarize themselves with.