Sony Xperia XZ2A Manual page 192

Handset dials number. Call begins when other party answers.
Calls to Landline Phones/Cell Phones in Country of
Stay
Place calls the same way you would within Japan.
Do not enter country code or omit first 0 from phone numbers.

In Home Screen,
xperia-xz2a_12_Global Services.docx
5
(Apps) (Phone)