This is a core block and thus available by default in Gutenberg WordPress editor. No download required.
The WordPress Page Break Block in Gutenberg allows you to break your content into multiple pages within a page or post. This simply paginates your content to multiple parts. Also displays the numbered pagination below the content.
Page Break Block Features
This page break block is really simple and does not have any options in the toolbar or sidebar.
The page break block added in the gutenberg editor
The page break block has no additional options for now.