Hi StephenWu2003,
Welcome to the Apple Community,
where some of us do our best to help each other troubleshoot.
Wondering which device (the PC?) you used to put the Word files onto iCloud,
and which iPad app you are using when you try to edit the Word documents ?
The Word documents may be read-only because they are in the wrong format for the iPad app ?
(Pages on iPhone, iPad, Mac, and online at iCloud.com use the same file format.)
(Eg: Are you able to edit them ok in the Pages app?)
Or
The originator of the files may have designated them read only
.... so may need to change that, to allow editing.
Apple support has articles online that may or may not help / guide you.
Formats you can open in Pages
You can open these file formats in Pages on iPhone, iPad, Mac, and online at iCloud.com:
- All Pages versions
- Microsoft Word: Office Open XML (.docx) and Office 97 or later (.doc)
- Rich Text Format (.rtf/.rtfd)
- Plain Text files (.txt)
Intro to word processing and page layout documents in Pages on iPad
(Pages is both a word-processing and page layout app rolled into one,)
https://support.apple.com/en-au/guide/pages-ipad/tan6129a1862/ipados
If you can edit a document ok in Pages,
you might need to export a copy as a Word document for the PC.
(Pages opens both Word and Pages doc ok ... PC might not open Pages docs.)
Convert Pages documents to PDF, Microsoft Word, and more
https://support.apple.com/en-us/HT202227
Hope this helps you :-)