Hello,
I hope you're doing well, and we apologize for the delayed response and the trouble.
The app or the online services do not support the Arabic language yet. You can use the Adobe Wish form to file a feature request: https://adobe.ly/3EDkrzZ
To know more about the Acrobat online services, see this article: https://adobe.ly/3X5SEhU
Thanks,
Anand Sri.