The error function is defined as

erf(x) will evaluate by default only when the result is an exact value, or when the input x is a floating-point number.  When x is a symbolic expression, it will remain in function form so that it can be manipulated symbolically  or as part of a larger expression.  

If x is an array, the result is an elementwise mapping over x.

erfc(x) is the complementary error function, that is, $1-\mathrm{erf}\left(x\right)$.

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$\mathrm{erf}\left(⟨⟨1.286495\,2.540680⟩|⟨7.354414\,6.899301⟩⟩\right)$

$\left[\begin{array}{cc}0.9311463225& 1.\\ 0.9996731879& 1.\end{array}\right]$

$\mathrm{erfc}\left(⟨⟨1.286495\,2.540680⟩|⟨7.354414\,6.899301⟩⟩\right)$

$\left[\begin{array}{cc}0.06885367755& 2.460874117\times {10}^{\mathrm{-25}}\\ 0.0003268121343& 1.720286965\times {10}^{\mathrm{-22}}\end{array}\right]$

The MTM[erfc] command was introduced in Maple 2021.

For more information on Maple 2021 changes, see Updates in Maple 2021.