Prophet is a procedure for forecasting time series data based on an additive model where non-linear trends are fit with yearly, weekly, and daily seasonality, plus holiday effects. It works best with time series that have strong seasonal effects and several seasons of historical data.
A big advantage of the Prophet model is that it provides an interpretable decomposition of the data that is observed or forecasted into seasonal, trend, and holiday components. This is useful if you want to understand why you are seeing certain patterns on certain days. Additionally, Prophet is relatively computationally efficient.