There are lots of different ways to get to Mexico. You can take a boat, a plane, or even drive. I'm going to do a combination of two of these. On Thursday, June 25th, I will fly from Tallahassee, Florida, to McAllen, Texas (changing planes in Dallas). Then, the next day on Friday, we will drive to Fresnillo, Mexico (the town where I will be living). This will take many hours and most of the day on Friday.
In order to go to other countries, you have to have a passport. Since I am a citizen of the U.S.A, I have a U.S. passport that looks like the one in the picture. When you cross international borders, they usually stamp your passport in the inside to show the dates you arrived or left on.