Hello friends,

       Can you tell me How to SEO of multilingual website..? 

Create two folders on your site, one for English, one for Arabic, then build links to both in the appropriate language.

Also, make sure it's easy to jump from one version of the site to another, but optimize URLs in each language. That's pretty much all you need to know.

Use Dedicated URLs. One of the main fears with multilingual sites is duplicate content. ...
Apply hreflang Tags. ...
Stick to One Language Per Page. ...
Translate your metadata. ...
5. Make sure your website loads fast.

Hi Friends,
The first step in optimizing a site for multilingual SEO is to plan out exactly what you want to do.

1. Decide which languages to target
2. Decide on whether to use a multilingual or multiregional SEO approach (or both)
3. Decide which content to translate
4. Consider multiple top-level domains (TLD)
5. Consider subfolders/subdirectories
6. Consider subdomains
7. Just avoid URL parameters
8. Learn how to add hreflang tags (syntax and example)
9. Add the hreflang x-default tag
10. Add meta language tags for Bing
11. Instead of using redirects based on location, make sure visitors can easily find how to switch languages
12. Avoid machine translations and block automated translations
13. Get a native speaker to translate
14. Do keyword research in other languages
15. You can do link building to further boost your multilingual pages
16. Hire marketers who are fluent in the language
17. Use a tool like Monitor Backlinks to track results and find link building opportunities