The information is available online and is easy to find. There have also been many discussions on the forums here that a quick search would have displayed.
Note: Most newer devices will be VoLTE enabled as they become available. Devices not purchased from TELUS will not be VoLTE enabled at this time.
VoLTE may be available for non-Telus devices at some point in the future but we'll have to wait for announcements from Telus when they become available.
"Devices not purchased from TELUS will not be VoLTE enabled at this time." I have an Iphone 6 Plus which was purchased directly from Apple - unlocked. It was not ever a "telus" phone as far as purchasing one oriented towards Telus. However, it has been using VoLTE on the TELUS network for about a year now. Don't believe everything you see, hear or read. It is my understanding that iPhones get their settings via a "carrier settings update" which allows non-Telus iPhones to behave like Telus iPhones. I expect there isn't such a straightforward way for Android phones..
Checking your APN settings might be a good place to start. If the phone has the same model number as the one Telus sells, then it should work. Some phones do require enabling VoLTE in the carrier settings of the device. Most Android phones has these options under Settings, Network & Internet, Mobile Network, Advanced, and enable Enhanced 4G LTE Mode. For versions of Android earlier than 8, go to Settings, More, Cellular Network Settings, and enable Enhanced 4G LTE Mode.
Although it is important to check your settings to make sure you can connect to the internet, the "non Telus" phone is in all liklihood going to have the correct APN settings or it isn't going to be able to get on the internet.
However, you'll note that the carriers (other than Bell with their video calling) will say that the data used in VoLTE does NOT come off your data bucket. This is because the "APN" used for the VoLTE is a different one than is used for normal data, that's how it is segregated, I believe...and we can't set this specifically.