Commands may be entered in 2D math as they are entered in 1D math. This is called command form, as the command name is typed in full. Here is an example using the int command, using both 1D and 2D math input.
$\frac{{344}}{{15}}$
 (1.1) 
>

$\mathrm{int}\left({x}^{2}\+\frac{x}{5}\,xequals;0..4\right)semi;$

$\frac{{344}}{{15}}$
 (1.2) 
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:
${\int}_{0}^{4}{x}^{2}\+\frac{x}{5}DifferentialD;x$
$\frac{{344}}{{15}}$
 (1.3) 
Additional forms are available through commandcompletion. 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:
$\mathrm{PV}{\int}_{1}^{2}\frac{1}{{x}^{3}}DifferentialD;x$