@Sandra16 not surecwhich password you are trying to change but I assume it is the one used to connect to the wifi in which case follow thecsteps here https://www.sky.com/help/articles/find-and-change-your-wireless-password.
There is a bug in the Sky hub's firmware which affects many Apple devices so if at all possible use a different device but if you have to use an iPhone or similar use Chromecrather than Safai and be prepared to have to use multiple attempts before the change sticks.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
