What does the term unlocked with verizon mean?

I was pre-ordering iPhone Xr, and chose Verizon as my carrier. At the last step, beneath the price, "unlocked with Verizon" was written. Could this device be used with international carriers?

Iphone not respoding

I have an iphone 8 and it is frozen. It is letting me unlock it and look at notifications, but it won't let me go away from the screen you get when you double tap. I tried to hold down the power button to reset it, but it won't let me. I can swipe up and look at the control center, but i can't do anything.

Will a charging wall block of 5V 2A ruin a powerbank if the powerbank supports up to 20V-1.5A (30W) from its USB-C input?

My powerbank's input supports 5V-3A, 14.5V-2A and 20V-1.5A (30W) and I was wondering if recharging this powerbank with a 5V-2A wall charger would ruin the powerbank if plugged into its USB-C input. That supports up to 20V-1.5A (30W)

It is my understanding that in order to enable fast-charging on my new powerbank, I would need at least a 30W USB-C PD wall charger and a USB-C to USB-C cable attached between my powerbank and the 30W PD wall charger. Replace USB-C to USB-C cable with lightning to USB-C if charging an Apple iPhone.

Added (1). I'm probably as confused as you are, and I'm sorry if it is really confusing.

Added (2). I also intend to charge my iPhone X/XS Max with this powerbank, but not sure if the chip inside these phones will allow fast charging from this 20V-1.5A (30W) powerbank.

IPhone 7 made strange noise?

I was just holding my phone texting and whatever, sound off, and it made this really
high pitched beeping noise for 3 seconds, and it also vibrated while doing so. This has never happened before, and my phone is fairly new. Any idea what this is?

How can I fix this problem on my iPhone 6?

Every time I turn my phone off & turn it back on & receive messages they only pop up on my lockscreen. But once I unlock my phone and try to go to the actual messages, the message no longer pops up. How can I fix this?