How to re enable find my phone when it has been disabled

If the device is with you then you can enable it otherwise NO.

Set up your iPhone, iPad, iPod touch, Mac or Apple Watch

To set up Find My on your iPhone, iPad, iPod touch, Mac or Apple Watch, sign in to the device with your Apple ID, turn on location sharing, and turn on Find My [device]. You need to set up Find My before the device is lost.

Set up Find My on all your devices - Apple Support (IN)