some of the PDF file in Adobe Cloud become “blank” on ipad while it’s normal on notebook

No 

the file still displays same as before 

Hello Chau,

I hope you are doing well. I am sorry for your experience with reading PDFs on Acrobat Reader Mobile.

The screenshots look like an issue with the font family embedded with the PDF file. Please share the document file with me [if it contains sensitive information, you can share the same with me through private message. To do so:

1. Click on my profile name;

2. On the next page, click on the option that says send a message, and this will redirect you to the messaging page]

Sharing the file will help me check for the file properties and better assist you.

In the meanwhile, I would suggest you try to view the same file on the document cloud portal and check if it shows up there or not.

Link for Document Cloud: https://acrobat.adobe.com/

I am looking forward to your reply.

Thanks,

Souvik.