duplicate contacts on iCloud.com
I see duplicate contacts on my iphone and when signing in on icloud. I don't see any options to merge/remove duplicates
Duplicate contacts are viewed in iPhone if you set up various accounts using gmail , yahoo ....etc and the iPhone is synced ( signed in with same Apple ID and password on the same network ) Set up and use iCloud Contacts - Apple Support they can be deleted from iPhone individually Manage and delete contacts on your iPhone, iPad, or iPod touch - Apple Support
But there is no way to select all duplicate contacts in iPhone as if compared to Mac .
In Mac there is option to merge duplicate contacts as the data base of Mac is larger than an iPhone .
In case if your iPhone and Mac are synced see the thread https://discussions.apple.com/thread/253109101