Iphone can't get onto internet outside my home?

When I go outside my home and try to access the internet on my iphone it won't seen to connect.

This issue has only just started in the last week or so. Before, I could use the internet outside and go on youtube etc without any problems. Does anyone understand why its not working now and how do I fix this?

IPhone carriers - SIM Cards?

I'm looking to buy an iPhone, and the one I'm looking at doesn't have the carrier listed and the seller isn't replying.

So my question is, if the carrier isn't right for me, can I just take out and replace the SIM card with a card from my carrier? Or is it, like, set?

Is there a way to unlock the phone to a different carrier if it's not on the right one?

The carrier I'm going with is one that carries iPhones, so I just need to know that if the phone comes with a separate carrier, can I change that?

How to stop receiving text messages and phone calls on 2 iPhones?

IIm letting my mom borrow an extra iPhone I have (iPhone 6 Plus and I have a 6s plus) and were receiving each other s messages and calls on both iPhones. She s signed into her iCloud account on the phone and IIm signed into mine on my phone so why are we still receiving each other s texts and calls?

What is iTunes used for exactly?

Because I'm wondering whether I should delete it from my PC. I have iPhone but I don't have any music on it, and don't plan to. Is this all iTunes is used for? If so, then I will uninstall it.

I want to sync music to my iPhone 5s but I don't know what I'm doing?

I just bought an iPhone 5s and I'm trying to sync music onto it. I have a few apps like Netflix, Hulu, and Facebook, nothing major and a few photos. I'm using my wife's laptop but we both have 2 different accounts on the one laptop, hers being the admin account. She has her own iTunes account and her own iPod shuffle.

I installed iTunes on my computer account and put music on it and linked it to my own iCloud account. When I plug in my iPhone and I try to manually manage music, a window pops up and says,

" The iPhone "My iPhone" is synched with another iTunes library on "My Wife's Computer". Do you want to erase this iPhone and sync with this iTunes library?
An iPhone can be synced with only one iTunes at a time. Erasing and syncing replaces the contents of this iPhone with the contents of this iTunes library. "

What does this mean? If I press the "Erase and Sync" button, what will happen? Is my iPhone permanently attached to my wife's iTunes or computer?

Can you have 2 different iTunes accounts on 1 computer?

Thanks for all information you can give me, I'm new to this whole Apple thing.