Placeholders? “Because question-detail text is not showing”

How do i put this like in this screenshot = https://postimg.cc/hQRxb68J
or perhaps
A Place holder? (A placeholder would be extremely important)
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How do i add placeholders? For example
the large question box (i.e: The large box below the “Title” box) – i want to put something like the text “ask your question here…” Or something else like “put your answer here” … I just want to put place holders on all the boxes.. – there are 4 boxes 1.-the title box, 2.-the question box, 3.-the comment box(which already has a placeholder text) and 4.-the reply box – – i just want to know how to put placeholders on each
Is there any easy or straight-foward alternative?