Files app “operation not permitted”

how to fix operation not permitted in iPhone XS Max?? Help me please

Hey there MazenMoha1996,

Thanks for reaching out to Apple Support Communities. I understand that you’re having an issue saving files to the Files app on your iPhone. I’ll be happy to help with this.

To verify, if you try saving the file to another location with Files, like iCloud Drive, does the issue continue? If not the following steps may help:

• Update your iPhone, iPad, or iPod touch to the latest iOS, or iPadOS.
• Set up iCloud on all of your devices and turn on iCloud Drive.
• Make sure that you’re signed in to iCloud with the same Apple ID on all of your devices.
• If you want to upload, download, or share files using cellular data, open Settings, select Cellular, scroll down to iCloud Drive and any third-party cloud services you use, and turn it on for each service. 

You can read more about this here:

Use the Files app on your iPhone, iPad, or iPod touch

Regards.