Can I upload part of my documents on icloud ? if yes how ?

When iCloud Drive and desktops and documents are turned as on https://support.apple.com/en-in/guide/mac-help/mchle5a61431/10.14/mac/10.14

Suppose there are ten documents saved in iCloud.com , you can drag and drop say three documents in other location , the part of documents will be uploaded on iCloud .

See the section - Move items to your Mac and remove them from iCloud Drive

in the article https://support.apple.com/en-gb/guide/mac-help/mchl1a02d711/10.14/mac/10.14