You should be able to enable encryption on Android devices running Android 4.0 (Ice Cream Sandwich) or later. As far as I know, any device running Marshmallow has encryption as an option. However, unless you have a pretty new device with a 64-bit ARM CPU, performance is going to take a significant hit if you encrypt your device. It’s a balancing act - how much performance are you willing to give up for additional security?
Personally, the first Android phone that I’ve used encrypted was a Nexus 6 that came with encryption enabled by default. There may be a slight performance penalty, but it is not an issue with the higher end hardware. On the other hand, I had an older mid-range LG that performed so poorly when encrypted that it was unacceptable. If you have older, slower hardware, the best option might be to forgo encryption and just make sure that you use screen lock with a strong password or pattern. Unfortunately, it takes a long time to encrypt a device, so set aside some time if you want to test it on your phone.