Hi @Lynne1948, welcome to our forum!
The Xperia L1 supports Wi-Fi calling, but to use this feature, your device needs operator-customised software and your subscription (incl. SIM card) must support Wi-Fi Calling for the device model you're using.
I would recommend that you get in touch with your operator and see if you have the correct customization to be able to use this in their network and if your subscription is setup correctly.
I hope that helps! 
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