  In this article, we describe the structure of the $R$-algebra of Drinfeld
modular forms $M(\Gamma_0(T))_R$ (resp., $M^0(\Gamma_0(T))_R$) of level
$\Gamma_0(T)$ and the structure of mod-$\p$ reduction of
$M_{\mfp}^0(\Gamma_0(T))$ for $\p \neq (T)$. As a result, we are able to study
the properties of the weight filtration for $M_{k,l}(\Gamma_0(T))$. Finally, we
prove a result on mod-$\p$ congruences for Drinfeld modular forms of level
$\Gamma_0(\p T)$ for $\p \neq (T)$.
