Question

When documenting R functions in a myfunction.Rd and whole packages
in a mypackage-package.Rd, which tags are compulsory?

By “tags”, I mean those things that look like \somename{}. For example:
\item{}
\title{}
\examples{}

Answer 1

This is described in Section 2.1 – Rd format of Writing R Extensions. Look for “mandatory”.

For functions, the mandatory sections are:

\name{name}
\alias{topic}
\title{title}
\description{...}
\usage{fun (arg1, arg2, ...)}
\arguments{...}

For packages:

\name{name}
\alias{topic}
\title{title}
\docType{package}