Officially, as the Shure SM7B is a dynamic microphone, it does not require phantom power to be used. However, in real world situations, due to the low output of the Shure SM7B (-59.0dB) a lot of users will pair it with a gain booster such as the Cloudlifter CL-1, and most of these require phantom power to work. Most audio interfaces with built-in microphone preamps are designed for use with condenser microphones which do not require much gain, so only provide only 40 to 50 dB of gain. Ideal recording volume is around -20dB to -5dB, so a preamp with an output volume of 40dB would be in theory a great choice, but it's not always that straightforward.