Hi Texgirl56,
Thanks for contacting Apple Support Communities!
We understand that you're unable to connect your Plantronics Voyager Legend Bluetooth headset to your iPhone.
Are you able to connect any Bluetooth devices to your iPhone at all?
Also, check out the troubleshooting steps outlined in this article which will help to isolate this behavior further: If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch - Apple Support
1. Make sure that your Bluetooth accessory and iOS or iPadOS device are close to each other.
2. Turn your Bluetooth accessory off and back on again.
3. Make sure that your Bluetooth accessory is on and fully charged or connected to power. If your accessory uses batteries, see if they need to be replaced.
4. If there's an app that you use with the Bluetooth accessory, go to Settings > Privacy > Bluetooth on your iOS or iPadOS device, and make sure that you've turned on Bluetooth for the app.
If you still can't pair or connect your Bluetooth accessory
1. If you previously connected your Bluetooth accessory to your iOS or iPadOS device, unpair the accessory, put it back in discovery mode, then try to pair and connect it again.
2. If you can pair your accessory with some devices but not your iOS or iPadOS device, unpair the accessory from your other devices. Then try to pair with your iOS or iPadOS device again.
3. Check with the accessory manufacturer to make sure that your accessory supports your iOS or iPadOS device.
4. If you still have any of these issues, contact Apple Support:
You can’t turn on Bluetooth or the setting is grayed out.
You can’t connect any Bluetooth accessories with your device.
The accessory manufacturer confirmed that your accessory is working correctly.
We hope this helps.
Cheers!