A programmer create software through a process called programming or coding. The purpose of programming is to develop an executable computer program that will automate performing a specific task or solving a given problem.
Programming involves activities such as analysis, design, generating algorithms and implementation of algorithms in a target programming language. These activities are also called as Software Development Lyfecycle (SDLC).
A computer platoform might understand certain language, and is usually called a low level programming language. A low-level programming language is a programming language that provides little or no abstraction from a computer's instruction set architecture; commands or functions in the language map closely to processor instructions.
However, it might not be that easy to learn and understand such a language. Therefore, there are high level languages closer to your speaking language like English. There will be other software, like compilers or interpreters, that can convert a high level language to a low level machine language before executing them.
A compiler is a computer program that transforms source code written in a programming language into another computer language, often in a binary form, that is understood by the computer platform or operating system.
An interpreter is a computer program that directly executes instructions written in a programming or scripting language, without previously compiling them into a paltform specific code
Compiled languages uses a compiler to translate the source code to platform/operating system specific form and then this compiled form is taken to all computers running using that platform/operating system. Interpreted languages generally compile line-by-line and execute them.
Newer programming languages like Java, Python etc. uses a combination of compiler and interpreter; a compiler may output some form of intermediate bytecode (Java's .class files or Python's .pyc files), which is then executed by a bytecode interpreter (Java Virtual Machine or Python virtual machine).