Your question is not very clear and you provided no example document.
\documentclass{article}
\begin{document}
This is a line
This is also a line
\end{document}
Is the standard markup for two paragraphs and adds no extra vertical space:

Perhaps you are using a class that instead of indentation uses vertical space to separate paragraphs, such as
\documentclass{article}
\usepackage{parskip}
\begin{document}
This is a line
This is also a line
\end{document}
Which produces

In either case, this is a two-paragraph document and quite different from
\documentclass{article}
\begin{document}
This is a line\newline
This is also a line
\end{document}
which is a one-paragraph document with a forced linebreak.

as is this:
\documentclass{article}
\usepackage{parskip}
\begin{document}
This is a line\newline
This is also a line
\end{document}

\newlineor\\force a linebreak within a paragraph and should only very rarely be used. So the question is, why do you need a new line? If it isto start a paragraph, a blank line is the correct input. – David Carlisle Feb 25 '22 at 10:28\parand\parfinelaizes paragraph and next line is next paragraph, i.e. next line. – wipet Feb 25 '22 at 10:45