Maximize is the default setting for the Audacity Amplify effect. You can then set it to different gains if your want to. Very slightly more work for more useful functionality. It's often a good idea to leave about 0.5dB headroom in case the peaks cause overshoot in any further processing.
I have a normalize command line tool on my GNU/Linux system that does the same, and very handy for quickly bringing a batch of files up to the same peak level: