I think you mean forced page break?
There're several threads about this topic.
In simple words, you can insert some code like this
<div style="page-break-after:always"/>
That's the forced page break in ePub, works like page break in MS Word.
Never use blank lines to separate pages.
But I don't know to do it for Kindle Mobi.
btw, an ad for my ePub maker,
it can convert Word page break, section break
to ePub perfectly.
so you needn't worry about this.