Arabic term (edited): وارد

Incoming no. = رقم وارد

Incoming date = تاريخ وارد

As to الهيئة, you know we cannot help you with that without context. It all depends on what the entity is. For example, when I worked with the Royal Commission (R.C.), it was called الهيئة الملكية

In that context, we translated

R.C. Incoming no. = رقم وارد الهيئة الملكية

R.C. Incoming date = باريخ وارد الهيئة الملكية

And so on.