Send/receive data from/to Raspberry Pi to/from Arduino with HM-10 (Bluetooth LE module)
HM-10 is a BLE device. You'll need to understand BLE programming, which is quite different than classic Bluetooth.
There is no standard BLE service for serial communication. 
The best way on a Pi to use BLE is with the 


noble and bleno modules for node.js. 
Or start by playing with gatttool.   


If you are fit in Phyton:
The HM-10 style device will send notifications that the Pi's BLE device can read. Basically you need to 
attach a 'delegate' call-back function to the Peripheral object, 
and then wait for notifications. 
The call-back can then process the received data.
You'll have to install the bluepy lib on the PI. This sample code writes to an Arduino HC-10 device

import bluepy.btle as btle

p = btle.Peripheral("AA:BB:CC:DD:EE:FF")
s = p.getServiceByUUID("0000ffe0-0000-1000-8000-00805f9b34fb")
c = s.getCharacteristics()[0]

c.write(bytes("Hello world\n", "utf-8"))
p.disconnect()   


Here is some code for reading from an Arduino HC-10 device 

import bluepy.btle as btle

class ReadDelegate(btle.DefaultDelegate):
    def handleNotification(self, cHandle, data):
        print(data.decode("utf-8"))

p = btle.Peripheral("AA:BB:CC:DD:EE:FF")
p.withDelegate(ReadDelegate())

while True:
    while p.waitForNotifications(1):
        pass

p.disconnect()