My apple watch series 3 contacts doubles and triples names. How do I merge them on my watch.

Hi

The following steps may help:

On your iPhone, in the Contacts app, check that there is a single contact card for each of your contacts and that each card contains that contact's full name and phone number, along with their email address.

If you have not yet done so, enable iCloud Contacts:

• On your iPhone, tap Settings > [your name] > iCloud > enable Contacts.

If you have contacts from multiple sources and multiple entries for the same person have not been linked automatically (such that they are shown as a unified contact, with "Unified Info"), then manually link those contacts by following the instructions here:

• Hide duplicate contacts

Delete prior Messages conversations with the affected contacts on each device:

• Messages conversations need to be deleted separately on your iPhone and Apple Watch.
• On each device, to delete a conversation: when viewing the list of conversations in Messages, swipe left on a conversation and confirm to delete it.

Having made any changes in the Contacts app, on your iPhone, in the Watch app, go to: My Watch > General > Reset > tap again on Reset Sync Data.

• Nothing will seem to happen, but the process will run in the background / invisibly to you, so allow some time afterwards for it to complete.

If the issue persists, it may then help to restart both your iPhone and your Apple Watch again, turning both off together, then restarting your iPhone first:

• Restart your iPhone, iPad, or iPod touch - Apple Support
• Restart your Apple Watch - Apple Support