MIT is a permissive license, apart from a few details about copyright and warranty representations. It has three parts:
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so
...which means that anyone can do anything that they want to with the software and cannot restrict others from doing the same, including incorporating your code into another project and selling it.
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software
...which means that, if you use MIT-licensed code in another program, you have to say so.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO BLAH BLAH BLAH...
... which means that nobody is responsible in any way for how well the software works, or anything that happens as a result of using of the software.