Where can I find freelance Arabic-English translation tasks online?

If you mean by "tasks", projects that have already been translated, then you should check out the United Nations website. However, if you mean by "tasks" then you should first open profiles in Proz.com and Translatorscafe.com , and advertise yourself as a freelance translator, the language combination you work in, and your areas of specialization. I hope this helps.

try translatorbase.com, I haven't tried the projects in this website yet, but they keep posting interesting tasks. You may would like to try.

https://www.upwork.com/o/jobs/browse/skill/translation-english-arabic/