docs: add how to help translating doc (#6982)

HELP_TRANSLATING.md

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+[中文](./HELP_TRANSLATING_ZH.md) | English
+
+# How to help translating
+
+In this chapter, we will discuss how to help translating the documentation of Element Plus.
+
+## Background
+
+Before we did the upgrade of the documentation architecture, each documentation update needs 5 languages, which most of the contributors use online translator for their non-native languages, sometimes it would be not only inaccurate but also stressful to them.
+
+So we decided to give the documentation site an upgrade.
+
+- From webpack to Vite
+- From manually maintained to automated
+
+We took [Crowdin](https://crowdin.com) as our first step to make the documentation site more automated.
+
+## How do I translate the documentation?
+
+1. Create an account on [Crowdin](https://crowdin.com), it is recommended that you use your GitHub account to authorize Crowdin.
+2. Go to [Element Plus](https://crowdin.com/project/element-plus) project.
+3. Choose the language you want to contribute to.
+4. Find the file you want to translate.
+5. Do the translation.
+
+That simple, and the UI is very intuitive to use, you should have no trouble using it.
+After you submit your work, it would be online once the translation is approved by proofreader.
+
+## How can I become a proofreader?
+
+You can [raise an issue](https://crowdin.com/project/element-plus/discussions) on Crowdin to us for becoming a proofreader of the language you wish to be.

HELP_TRANSLATING_ZH.md

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+[English](./HELP_TRANSLATING.md) | 中文
+
+# 如何帮助翻译
+
+本文档主要针对如何帮助 Element Plus 的内容翻译。
+
+## 大背景
+
+在给文档站做升级之前，每一次文档改动都需要改五种语言，大部分的贡献者都只会自己的母语和一门外语，大部分的贡献者也会寻求翻译器来翻译其它自己不熟悉的外语，而翻译器翻译的内容对母语者可能造成误解，并且对贡献者来说也是一件麻烦的事情。
+
+所以我们决定把文档站做升级。
+
+- 从 Webpack 升级到了 Vite
+- 从手动维护的到自动化
+
+我们采用了[Crowdin](https://crowdin.com)作为自动化的第一步来升级文档站。
+
+## 我怎么才能帮忙贡献翻译的内容？
+
+1. 首先在 [Crowdin](https://crowdin.com) 上创建一个账号， 这里我们推荐使用 GitHub 的账号做第三方登录，方便快捷。
+2. 去到 [Element Plus](https://crowdin.com/project/element-plus) 项目.
+3. 选择你想要贡献翻译的语言。
+4. 选择你想要贡献翻译的具体文件。
+5. 翻译。
+
+以上就是如何参与贡献翻译的全部步骤，Crowdin 的界面和交互设计非常的人性化，在使用过程中应该不会遇到太多难题。
+当你提交完你的翻译之后，它会在翻译审核通过之后上线。
+
+## 我怎么样能成为翻译审核？
+
+你可以在 Crowdin 里[提一个 issue](https://crowdin.com/project/element-plus/discussions) 来申请成为一个翻译审核。

README.md

@@ -105,6 +105,10 @@ a proofreader [![Crowdin](https://badges.crowdin.net/element-plus/localized.svg)
 For now we are only showing English and Chinese for resource reasons, but we are looking forward to translate it into more languages, please go to the link
 above and leave a message if you want to help translating Element Plus into your desired language.
 
+### How to help translating
+
+See how to help translating in [Translating Element Plus](./HELP_TRANSLATING.md)
+
 ## Stay tuned :eyes:
 
 Join our [Discord](https://discord.link/ElementPlus) to start communicating with everybody.