Commands may be entered in 2-D math as they are entered in 1-D math. This is called command form, as the command name is typed in full. Here is an example using the int command, using both 1-D and 2-D math input.
Some commands allow alternative forms of entry that use mathematical notation. Many of these forms are available in Maple's palettes. For example, the integral computed above can be entered using the definite integration template from the Expression palette:
Additional forms are available through command-completion. For example, if you type int and invoke command completion, you will be offered, among other choices, the option to compute the Cauchy principal value: