How to send string over bluetooth LE from Arduino
I've used a HC-O6 Bluetooth device connected to pins 2 &amp; 3.  After setting up SoftwareSerial to use those pins, I sent my messages to that SoftwareSerial using the normal method as a "string"/character array.

I would assume this would work the same with a BLE device that used a serial connection.

I'm not familiar with the AdaFruit Feather, but it looks like it's supposed to be a direct Arduino Nano competitor.  You might need to use a different library, but the idea should still be the same.