Apple fast charge and the original charger it is different, fast charge it means that charging is relatively fast, depending on whether the phone and the original charger, but it is not harmful to the battery.
Like fast charging technology, there are also some brands such as brand fast charging can replace Apple's original charging in the short term, and third-party USB-C chargers can be used on the iPhone as long as they support the USB Power Delivery (USB-PD) standard. The original charge is an ordinary charging method, which is relatively slow.
Fast charge is fast charging speed, generally one hour can be full.
The primary rush is normal speed, and it takes about 3-4 hours to fill.