how do I create a duplicate contact in iCloud from same company so all I change is name and tel number

See the article https://support.apple.com/en-za/guide/icloud/mmfba742ff/1.0/icloud/1.0

You don't indicate which device you are using to create the duplicate, but you can use the same contact. Just use edit to add a telephone number, and when adding the phone number create a "Custom Label" for that phone number.