On my iPhone I have bars and a wifi symbol, what exactly do they mean?

You iPhone sends and receives data multiple ways. The two primary means are via cellular data (from cell phone towers and satellites) and WiFi signals (from a wide variety of routers in the world, including your house). The bars represent the signal strength from cellular sources and the fan shape represents signal strength from WiFi sources. They work simultaneously, often handing data back and forth.

Both sources allow for the transfer of audio, video, phone calls, still images, etc.

What @cookieman describes is if you have both sources enabled for receiving. But you can restrict how data gets to your phone if you are concerned. Going into Airplane mode means everything will get to you via wi-fi. And you can turn wi-fi off if you want.

Alternatively, looking at your Cellular settings you can restrict or limit how your phone does or does not connect to wi-fi calling or receives data from cellular connections.

@zenvelo Why would a person want to limit wi-fi?
(Sorry if I’m derailing your question @JLeslie.)

@chyna Some people don’t want to inadvertently connect to an unsecured network.

My company did not allow use of cell phones for company business for a long time for that reason. It wasn’t until they could control the back end access to our business computers that they let us use personal phones.

I did not understand they work at the same time. I always thought if I’m connected to wifi then I am not using cell towers at all.

I also did not understand airplane mode only cuts off cellular data. I thought it cut off being “online” in every way. When I go into airplane both the bars and the wifi symbol disappear.

@chyna Not a problem, I put it in social on purpose hoping to get extra information.

My wifi always asks me if I want to join a new network before connecting.

@JLeslie I happpen to fly a lot (flying from Albequerque to Oakland tonight!) and at most airports, the cell reception while boarding will work but the wi-fi rarely works until the plane is at altitude. But then one goes into “Airplane mode” at departure, but the plane’s wifi wil kick in above 10,000 feet.

Airlines do filter wifi so one cannot stream over a private conncetion but you can stream from the airline sponsored movie and TV show content,

@zenvelo Actually, I used wifi on board a few years ago. I didn’t really understand how that worked. It is so long ago I don’t remember the settings on my phone.

Yes, as @zenvelo mentioned, you can toggle both or each on/off at will.