Phones Chargers in Europe.

You’ll need two different types of plug adapters - one for England and one for the other countries. They will allow you to use your charging cable there. Edit: be sure to look at the fine print on your phones to make sure they’re dual voltage.

It's not your phones that require the correct current, but your chargers (charging blocks aka wall warts). Pretty much any original equipment phone charger (the one that came with your phone) made in recent years should work fine with either 110 or 220, but it's worth checking the fine print (often just etched/raised on the charging block) to be sure. If you have some cheap knock-off charging block you picked up in a gas station, check carefully.

Mostly what you're going to need is just the correct plug adapter for the countries you're going to. This adapter simply allows your US-style plug to fit foreign outlets. You can buy individual adapters for different countries or some kind of "universal" multi-country adapter with different plug configurations. I like this one - Flight 001 4-in-1 Adapter - have used it all around the world for many years and it has never failed me. Wife likes the bright colored plastic bits, which makes them harder to lose/forget. There are many other options. Simple.

You'll actually require 3 different adapters- Switzerland is different from Germany & France.
Safe travels!

I’ve always used the same plug adapter in Switzerland that I used in any other country on the continent. Never had a problem.

I’d ensure you have the adapters, but many hotels now have USB ports either on desks or wall outlets.

RE Swiss plugs.
Swiss 2-pin plugs are the same as the rest of Europe (except UK/Ireland)
Swiss 3-pin plugs (i.e. earthed plugs) are unique and require a different adapter.

Phone chargers are 2-pin, as long as your adapter is 2-pin Europlug type, it will work in Switzerland.
I have seen some cheap 2-pin adapters which are not the correct shape, and will not work in Switzerland.

I suggest you buy two items for your trip. The first is a multi-port USB charger. Double check to make sure they are dual voltage (110/220), That's mostly standard nowadays. We have a six port charger that allows us to use just one charger for our iPhones and iPads.

I also suggest you get a power bank, which is a rechargeable battery pack. On the last trip we took, I was running low with my iPhone before I could get back to the hotel to plug it in. I bought a power bank and use it often. The larger units are able to recharge two iPhones. At night, I plug it in to the charger at the hotel along with our other devices and it is fully charged for the next day.

ben,

The easiest and cheapest solution would be to just buy a couple of cheap Plug Adaptors and use those with your normal phone chargers. Most (all?) current mobile phone chargers are designed for operation from 100 - 240 VAC, so will work normally on European electrical systems. There are separate Plug Adaptor models for the U.K. and Europe. One issue with that approach is that outlets are sometimes few and far between in some European hotels, so charging more than one device at the same time may be awkward.

A more efficient solution would be to use a multiple USB charger as suggested in the previous reply. THIS model will charge four devices and is designed for use with 100 - 240 VAC voltages. A Plug Adaptor specific to the country would of course be required.

Ken has a good idea about a multiple USB charger. However, I'm going to suggest this one instead:

https://www.amazon.com/gp/product/B07JH9R89T/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1

It's newer, is slightly more powerful, and comes with the adapter plugs you will need. I'm using it now to charge the tablet I'm writing this on.