Type of charges

**I still have an iphone 7. What power charger should I use? … plus any other little details about charging that I likely do not know. thanks

…and do I still use an A to B? When would I need a B to C?

Older devices uses the plug connector of a usb a connector but newer cables have a usb c connector . There is really no B connector for most iphone type devices. Iphone uses the lightining connector and very old devices uses the micro.

So you can have
usb a toa micro, lightining or usb c (ends)

usb c to usually lightining or usb c ends (the usb plug will have a plug end to connect it to a wall (such as the anker nano).

Newer chargers will have a usb c connector on it for the new cables (to charge the charger and to use to charge things (the cable withe the charger can be a usb a to usb c or a usb c to usb c)

The older ones will be similar but will have a usb micro that is only to charge the charger…

Most of the charger will have the usb a to use to charge the devices but as stated the newer ones may also have a usb c to charge and to use to charge devices if you have the cable to do so).