In general you will be familiar with high level programming languages, such as PYTHON or JAVA. On the other hand there are low level languages, like C or the different dialects of ASSEMBLER.
The most recognizable difference between the two types is that a low-level language nearly directly operates on the instructions already available from the microprocessor and system components. These include commands like "read memory a position x" or "jump to line y in this file" but nothing in the style of "create an instance of an object" as the mircoprocessor would need a lot more translation work done to use this command on a limited set of operations. A high level language will support this advanced "translation" to give the programmer more options, but therefore will require a bigger toolset (in the form of a compiler or a runtime library)