Call recording, while not legal in every part of the world, is quite handy in certain situations. Some OEMs have decided to implement call recording into their default Phone applications, and sometimes hide it. There are ways to enable the feature, if it’s there but hidden, through Xposed Framewok modules or other apps.
On the older firmwares, such as 4.4.2, Sony had a hidden call recording feature in SemcPhone.apk. This feature was split over multiple applications. XDA Senior Member AndroPlus found a way to restore the call recording feature by extracting the Chinese variant of the ROM. The extracted CallRecording.apk can be flashed onto the device using one of the popular recoveries.
To make use of this feature, your device must be rooted. After flashing the archive, the feature can be found in the Settings → Call Setttings → Call Recording. Be sure to check if call recording is legal in your country before flashing this application. You can find the regulations in this Wikipedia article, but most likely the best way is to check with local authorities.