In my report, sometimes, the section label is getting completely at the bottom, or if sometimes not completely, after the section label, there is only one or two lines, like the picture below:
How do I move the section to a new page if after the section there is less than 5 lines to obtain a new page?
You can use the titlesec package, which has a nobottomtitles option (bottomtitles is the default).
It defines a \bottomtitlespace length, that defaults to 0.2\textheight. It is the minimal vertical space that must remain at the bottom of the page to allow inserting a sectioning command, and you can change its value with a renewcommand\bottomtitlespace{some other value}.
For details, take a look at § 3.3 of the documentation. I think it is better to set \raggedbottom in your preamble to prevent white spaces stretching across pages.
