Hello Parijatbarua,
We understand that you're unable to view or find email attachments when using iCloud Mail. We'd like to provide you with a few steps that may help resolve the issue:
1. Make sure you that haven't exceeded your iCloud storage limit. If you exceed your iCloud storage limit, learn how to make more space available in iCloud.
2. Make sure that you're using the latest version of software on your device.
3. Make sure your browser is up to date
4. Clear your browser's cache.
More details here: If iCloud Mail isn't working
Let us know if this helps.
Take care.