Every carrier I know of offers voicemail as an included part of their service. My phone service will be no different. However, there will be a couple of differences. First, there will be a unified voicemail. This will mean the customer can have 2 or more telephone numbers, but will only have 1 voicemail account for all of their numbers. This means the customer can have a cellular line, a SIP line, and a Voicemail line – but one voicemail box. For access to voicemail via cellular, the customer will press and hold 1. To access voicemail via SIP, the customer will dial *86.
There are a couple of exceptions. First, Second Line phone numbers will be given their own voicemail. This will allow you to use your second line for other roles than what your primary line is (such as a work number). Next, a primary account holder can have up to 4 secondary accounts. Each secondary account will have their own unified voicemail service. As with the primary account holder, the secondary account holder will be able to press and hold 1 via cellular, or *86 via SIP.