How do I find a iPhone that has been lost for a week

You can only track a lost or stolen phone if it:

1. Is Powered On
2. Had Find My enabled before it went missing
3. Is connected to a network

See this link to see more information on what to do if your phone is lost or stolen --> If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Then you cannot track it, sorry.

If you have AppleCare+ Theft and Loss or you paid for theft and loss from your carrier as an added charge, you can file a claim. If you didn't, you'll need to buy a new phone.

Do contact your cellular provider and ask if they can blacklist the phone.

If u haven't found ur iPhone in a week did u have find my phone on and location if not did you apple care and insurance and warranty cause you mide as well replace the phone cause ur not going to find it some one has it

try using "Find My" app

Try

1) Calling it from another phone

2) Find My app.

Those are unfortunately the only ways.

If it is dead, you can't find it.

If find my is not enabled, you can't find it.

Your service provider can't help either.