if it is an Uno or Nano use SoftwareSerial to create a separate serial port for the HC06
SoftwareSerial is the worst choice. Better choices are:
1) The fastest, most reliable way to connect a device is to use a HardwareSerial port.
On any Arduino board, you can connect a device to the Serial pins (0 & 1). You can still print debug statements, and they will show up on the Serial Monitor window. The characters received from the device will not interfere with debug prints, and you will not see those characters on the Serial Monitor window. Debug print will also be sent to the device, but if it has a command format, it would ignore the debug prints as "invalid commands". For example, if you have to send "AT " at the beginning of commands for the device, don't do any debug prints that start with that sequence. The device will ignore all your debug prints.
However, when you need to upload a new sketch to the Arduino, you must disconnect the device from the Arduino RX pin 0. Otherwise, the device characters will interfere with the uploading data.
For Mega, Micro, Due and Teensy boards, you can connect a device to the Serial1, Serial2 or Serial3 pins.
For Micro and Leo (and other 32U4-based Arduinos), you can connect the GPS device to the Serial1 pins (0 & 1).
2) If you can't connect the device to a HardwareSerial port, you should download and install the AltSoftSerial or NeoICSerial library. These libraries only work on two specific pins (8 & 9 on an UNO). This library is very efficient and reliable. It uses one of the hardware TIMERs, so it may conflict with libraries that use TIMERs or PWM output (e.g., servo).
3) If you can't use the pins required by AltSoftSerial, and your device runs at 9600, 19200 or 38400 baud, you should download and install the NeoSWSerial library. This library is almost as efficient. It will help you avoid common timing problems caused by SoftwareSerial. It does not need an extra TIMER, so it can be used with most other libraries. It does use Pin Change Interrupts, but there is an option in the header file that allows you to coordinate other PCI usage with NeoSWSerial.
NeoSWSerial can be used with AltSoftSerial at the same time, allowing your sketch to have two extra serial ports.
4) SoftwareSerial is NOT RECOMMENDED, because it disables interrupts for long periods of time. This can interfere with other parts of your sketch, or with other libraries. It cannot transmit and receive at the same time, and your sketch can only receive from one SoftwareSerial instance at time.
AltSoftSerial and NeoSWSerial are available from the Arduino IDE Library Manager, under the menu Sketch -> Include Library -> Manage Libraries.