A face cloth and a washcloth are often used interchangeably, but they serve slightly different purposes.
A face cloth is designed specifically for gentle cleansing of the face. It is used daily to remove makeup, dirt, and oils without being too abrasive for the delicate facial skin, for example CloudCloth is made specifically for this purpose with a dual sided textile to offer both gentle cleansing on one side and exfoliation on the other. They are also the preferred choice when considering the environment as wipes and cotton wool are disposable items, whereas a face cloth can be washed and re-used many many times.
A washcloth is a slightly larger, thicker cloth usually made from flannel or towelling fabric for washing the entire body during a bath or shower. They are better for exfoliating and scrubbing tougher areas like elbows and knees. Both cloths play essential roles in maintaining personal hygiene, but their intended uses differ based on the areas they clean.
In the UK, the term flannel or face flannel is often used to represent this type of cloth usually found in towel sets and in the USA it is widely known as a wash cloth.