How can I change the font size of the title and the font size of the authors in Latex?

Question

I need a font size of 16pt for the title and 12pt for the authors. I'm writing an article class document in 11pt:

\documentclass[11pt, a4paper, twocolumn]{article}

Answer 1

This will let you put whatever font you desire in the title: (just replace \myfont)

\documentclass[11pt, a4paper, twocolumn]{article}
\begin{document}
\font\myfont=cmr12 at 40pt
\title{{\myfont Who knows}}
\author{{\Huge A.~U.~Thor}}
\maketitle
Paper.
\end{document}

You can also use \Large or \Huge instead of \myfont, to fit the rest of the document style (this way LaTeX will only change the size of the font)

Answer 2

As stated in a comment above and in many other questions on this site, it is a bad practice to add formatting markup in \title, \author or any command that has a semantics meaning (including sectioning commands).

Instead to the titlesec or titling packages (that are the "standard" answer), I would suggest to load the etoolbox package and use its \patchcmd command like this (for the title, the printing in performed by \@maketitle):

\documentclass[11pt, a4paper, twocolumn]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{etoolbox}

\makeatletter
\patchcmd{\@maketitle}{\LARGE}{\Huge}{\typeout{OK 1}}{\typeout{Failed 1}}
\patchcmd{\@maketitle}{\large \lineskip}{\Large \lineskip}{\typeout{OK 2}}{\typeout{Failed 2}}
\makeatother

\title{A simple example of \textbackslash Huge title}
\author{Nice and \textbackslash Large author}
\date{\today}

\begin{document}
\maketitle
\end{document}

yieding :

in place of

In order to know which replacement (here \LARGE and \large \lineskip) one has to perform, look at the definition of the command, by using :

• Either the \meaning or the \show commands printing command definition in the pdf and in the terminal respectively.
• Or similarly, for protected commands, the \ShowCommand (LaTeX2e fall 2020) or \showcmd (package show2e).
• Or, on the command line, texdef -t latex -c article -F @maketitle.

Answer 3

It is quite simple, download the template and remplace the command \title{Resumé title} in the template by the two following lines: \font\myfont=cmr12 at 15pt and \title{{\myfont I am the title}} and your problem is solved.....