Mathematica provides a number of integrated options for controlling output form and style of expressions. Among these are named *Form wrappers. These can be:
- overarching:
StandardForm[],TraditionalForm[] - general:
InputForm[],OutputForm[](plain text input/output or copying code to the web) - controlling number representation:
NumberForm[],PaddedForm[],ScientificForm[], etc. - specific for vectors, matrices, tensors and tables:
MatrixForm[],TableForm[] - displaying expression structure:
FullForm[],TreeForm[] - controlling compatibility:
CForm[],FortranForm[] - export format wrappers:
TeXForm[],MathMLForm[]
There are also a number of tools for specific styling, most notably Style[].
See also stylesheets on how to handle styles at a higher level.
Useful links:

