Some brands, such as Yamaha and Denon, include a step-by-step room calibration set-up and microphone with all their AVRs that will measure the response of your speakers with your room and apply an appropriate EQ that flattens any anomalies.
Other brands, such as JBL and Arcam, offer third-party software Dirac with premium models, or as an optional upgrade for budget models.
If you purchase an AVR from a dealer that offers installation, calibration will likely be included. However, if you’re someone who likes fine-tuning or you’re likely to make changes to your set-up, it's important to bear in mind that you won't be able to make further adjustments.
However, optimization software is by no means essential, and you can still calibrate a system manually using a Sound Pressure Level (SPL) meter (there are now decent SPL apps that work fine if you've also got a good phone with a decent microphone, though a dedicated meter is still the way to go if possible) and a tape measure. Even budget AVRs include an internal test tone and options to assign speaker distances and levels. Those installing a home cinema in an unusually shaped space will benefit more from calibration software, but for typical usage, it's not vital.
For more advice, check out our guide on how to set up your home cinema speaker system.