If you have a SIM Card, then yes.
Of course.
what is an unlocked cell phone
iPhone
Yes it will as long as it is GSM and it is unlocked
Having an unlocked phone allows you to use the phone with different carriers. Keep in mind some services may not function on an unlocked phone.
You can go into your settings on your phone to see if your data is turned on. If so and it is not working, you will need to take it to a T-Mobile store.
Leaving your cell phone unlocked is a risk that can lead to overages, additional fees, or fraud. If left unlocked in your pocket or handbag, your phone's buttons can be accidentally pushed quite easily, resulting in downloaded apps or unintentional text messages. Losing an unlocked phone could have more dire consequences, such as credit card fraud if you've been shopping on your smartphone. Adjust your preferences in your menu, and lock that phone!
Yes you can if you are on a mexican sim card/network. It is possible to text if both are on the same us network but you need signal for that network.
use your phone
One can purchase a legally unlocked phone from a variety of places. The United Kingdom sell phones unlocked for a higher, non-subsidized price, and even in the US you are still allowed to purchase an unlocked phone from your local cellphone store - you are just not allowed to unlock them if they already come locked.
Take it into a phone company that offer's the use of unlocked phones and they should activate it for you.
No. Get you phone unlocked if you are not sure.