Excel

Please read Access iCloud Drive files from your iPhone and other devices.

iCloud Drive can be used to store any kind of file including files created by Microsoft Excel or anything else.

Numbers can be used to open edit and save Microsoft Excel files. It is available on the App Store for both macOS and iOS and it's free. If you would prefer to use Microsoft products though I cannot help with them.

I don't know what a "mycloud" is. Do you mean iCloud?

Set up iCloud Drive - Apple Support

iCloud stores any kind of file, Microsoft Excel or anything else. If that does not answer your question perhaps you need to ask Microsoft, assuming "my cloud" is their product. Contact a third-party vendor - Apple Support:

• Microsoft products: Visit the Microsoft website.