Apple's mobile phone can't turn pages with the volume button. Turning pages with the volume button is a unique function of Android phones.

Press the volume button directly on the reading page to turn the page left and right. Generally, the up key is left turn, and the down volume key is right turn. Ios system does not support this function because it is closed, but in fact this function is useless. If you keep pressing the volume button, the volume button is easily damaged.