HC05 Bluetooth - why some use voltage divider and some not?
It looks they do that as a simple form of level shifting between 5V and 3.3V. If you have a device with 5V tolerant inputs, you don't need to do anything special. Check your data sheet for details on what is supported -- it's usually a nice selling point for 3.3V devices and is often called out on the first page / marketing material.

Check out the tips here in Chapter 8: http://ww1.microchip.com/downloads/en/DeviceDoc/01146B.pdf for more ways of doing level conversion.