Open the dialer app
Tap the menu (vertical ellipsis top right)
Select Settings > Calling accounts
Tap the SIM at the top
Tap select UIM/SIM card
for the settings regarding voicemail, call forwarding, call waiting, call barring etc.
Please note your options vary per mobile operator/carrier. The mobile operator may provide a self-service website to select and adjust more services.
Does this help?