That all depends on what you want to use it for and why you want to learn to code. There are 100’s of coding languages out there. You could even create your own. We first have to distinguish between high level language and low level language.
High level language (code) is one where the code you type is very user friendly, very much like a spoken, actual language. It is usually a good place to start and PYTHON is a good example.
Low level language (code) is one that has a more specific language to it. It is not as easy to read as the words used are less obvious, it is less user friendly but none the less is also a good place to start. It is where I started and I picked it up very quickly. C or C++ are good examples.
Generally people start with a high level language and migrate to one of the more specific low level languages but if you know what you want to achieve then going for a low level language isn’t a bad idea. Once you have leaned one language the others are pretty similar.
Here is your starter list…
Python: A popular general purpose language used very widely on many machines, for many purposes e.g. on the Raspberry Pi. Can be used for physical computing, games, web design, AI or big data.
C/C++: another extremely popular coding language. Used with the Arduino Uno for physical computing.
Talk about hardware next…