how to consolidate contacts

Apple has some suggestions in Get rid of duplicate contacts on iPhone.

You might have duplicate contacts in your iCloud account, or you might have entries for the same person in different accounts or sources: Gmail and iCloud for example. In this situation you can link them, to quote from the document says, "as a single unified contact."

Or you could go through them all manually to curate them yourself.

Oscpal Said:

"how to consolidate contacts"

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Managing Mailboxes:

If you want to keep them, then make a mailbox for bulks of addresses.

Use these Links:

• Organize eMail with Folders in Mail on iCloud.com - Apple Support

• Use Mailboxes to Organize eMail on your iPhone, iPad, or iPod touch - Apple Support