If it shows On Hold (Suspended) , then it is a payment issue. Click "Pay Now and Resume Services" to make a manual payment
If it shows active,
iPhone: Likely no extra work need to do as Telus will enable by default but hide the option. Still you can check
Settings->Cellular->Cellular Data Options->Voice & Data, enable 4G or LTE there
Pixel: Likely no extra work need to do as Telus will enable by default but hide the option. Still you can check
Settings->Network and Internet->Internet, click on the settings icon besides SIM 1, turn on 4G calling there
Samsung/ Other Android: Settings->Connection->Mobile Data, enable VoLTE there
Now, turn off Wifi first. Check if the phone status bar showing it is connected to 4G or LTE
Then make some calls, see if the signal indicator shows LTE or drop back to H or 3G while you are on the calls. If it stays with LTE, then yes, you are using VoLTE, and you can see if calls are any better.
give us more information like you just joined PM? was it working before? What phone you have?
or you can submit ticket with PM agent to refresh your account