You can use them both as the same meaning exept for some cases like standing up You have to use وقف and not توقف وقف الرجل the man stood up توقف الرجل the man stopped

وقف verb in past = stoped توقف = stopping

As per the circumstances, the meaning of وقف will be changed. وقف = vaqafa = توقف = thavaqqafa = to stop or come to a standstill. وقف = vaqafa = to stand up وقف = vaqafa = to hesitate وقف = vaqafa = to confront (وقف ( في سبيله = to interrupt or to block the way of ( وقف ( في ، الى ، مع to defend or to support (وقف ( ماله على = to endow or to donate for a charitable purpose وقف = vaqf = endowment توقف = Thavaqqafa = to stop, to hesitate, to depend on, to suspend توقف = Thavaqquf = breakdown or failure When we read or listen Arabic, we will understand the exact meaning of these two words by immediate attention of words mentioned after and before of وقف / توقف in the sentence. In Arabic, we say about this سياق وسباق Hope it will help you.

mustafa explained it very will . it depends on the word after it some times on the would sentence . such words you need to look it up on moaagam < arabic dictionary >

As per the circumstances, the meaning of وقف will be changed. وقف = waqaf = توقف = thawaqqaf = to stop or come to a standstill. وقف = waqafa = to stand up وقف = waqaf = to hesitate وقف = waqaf = to confront (وقف ( في سبيله = to interrupt or to block the way of ( وقف ( في ، الى ، مع to defend or to support (وقف ( ماله على = to endow or to donate for a charitable purpose وقف = waqf = endowment توقف = Thawaqqaf = to stop, to hesitate, to depend on, to suspend توقف = Thawaqquf = breakdown or failure When we read or listen Arabic, we will understand the exact meaning of these two words by immediate attention of words mentioned after and before of وقف / توقف in the sentence