Apple wireless charger does not randomly standard charging head, the official recommend users with their home USB-C charging head, if with 20W charging head, wireless charging power is 11W, and want the maximum 14W wireless charging, it is necessary to match the new 30W charging head.
Of course, now USB-C charging head is very common, Apple's 20W and 30W charging head is actually the standard USB-C PD specification, so users buy their own third-party is also compatible, but it is necessary to see that the charging head must have 9V\/3A or above PD charging support, in order to give the iPhone 12 fast wireless charging. If you want to charge the iPhone and Apple Watch at the same time, the charging head requires at least 15W.