ALL HC-05s are 3.3v, no ifs, no buts, no maybes, and no exceptions.
The 3.6 to 6v you see is the power requirement for the breakout board, with on-board regulator, that the HC-05 is soldered to. Even while this is the case, you might notice that the signal pins are still marked 3.3v.
It is possible to buy a bare HC-05, no breakout board, which requires a 3.3v supply, hence my comment in reply #2.
It is/was also possible to buy an HC-06 on a 3.3v breakout board, but it is not common, and I rather suspect about the only place it might be used is with a 3.3v pro Mini, or a close relative - also not common....
illustrations herein