Here are two quick ways (see below for a better way):
\hspace{1em}
following the \\
Preferred would be to use a paragraph structure and not use \\
in general. Then you can set \parindent
to the indent value.
The MWE:
\documentclass{article}
\raggedright
\begin{document}
\subsection{Light}
\textit{Evocation cantrip}\\
\textbf{Casting Time:} 1 action\\
\textbf{Range:} Touch\\
\textbf{Components:} V, M (a firefly or phosphorescent moss)\\
\textbf{Duration:} 1 hour\\
You touch one object that is no larger than 10 feet in any dimension. Until the spell ends, the object sheds bright light in a 20-foot radius and dim light for an additional 20 feet. The light can be colored as you like. Completely covering the object with something opaque blocks the light. The spell ends if you cast it again or dismiss it as an action. \\
\hspace{1em}%
If you target an object held or worn by a hostile creature, that creature must succeed on a Dexterity saving throw to avoid the spell.
\subsection{Light}
\textit{Evocation cantrip}\\
\textbf{Casting Time:} 1 action\\
\textbf{Range:} Touch\\
\textbf{Components:} V, M (a firefly or phosphorescent moss)\\
\textbf{Duration:} 1 hour\\
You touch one object that is no larger than 10 feet in any dimension. Until the spell ends, the object sheds bright light in a 20-foot radius and dim light for an additional 20 feet. The light can be colored as you like. Completely covering the object with something opaque blocks the light. The spell ends if you cast it again or dismiss it as an action. \par
\parindent=1em%
If you target an object held or worn by a hostile creature, that creature must succeed on a Dexterity saving throw to avoid the spell.
\end{document}

The problem with either quick fix is the, as a rule, \\
is a very poor and not recommended way to format lines. The problem with the 2nd \par
approach is that each new subsection will have to \noindent
all the header information, once \parindent
is set to a non-zero value. So I think a third way is best...
A better way would be to cook it into a macro structure, and use the \par
approach always (EDITED to permit multi-line header info):
\documentclass{article}
\usepackage[usestackEOL]{stackengine}
\raggedright
\strutlongstacks{T}
\newcommand\mysubsection[6]{%
\subsection{#1}
\setstackgap{S}{0pt}%
\Shortstack[l]{%
\parbox{\linewidth}{\strut\textit{#2}\strut}\\
\parbox{\linewidth}{\strut\textbf{Casting Time:} #3}\\
\parbox{\linewidth}{\strut\textbf{Range:} #4\strut}\\
\parbox{\linewidth}{\strut\textbf{Components:} #5\strut}\\
\parbox{\linewidth}{\strut\textbf{Duration:} #6}}%
\par\noindent\ignorespaces%
}
\parindent=1em%
\begin{document}
\mysubsection{Light}{Evocation cantrip}{1 action}{Touch}
{V, M a firefly or phosphorescent moss) with
a multi-line item tha goes blah blah blah blah}{1 hour}
%
You touch one object that is no larger than 10 feet in any dimension. Until the
spell ends, the object sheds bright light in a 20-foot radius and dim light
for an additional 20 feet. The light can be colored as you like. Completely
covering the object with something opaque blocks the light. The spell ends
if you cast it again or dismiss it as an action.
If you target an object held or worn by a hostile creature, that creature
must succeed on a Dexterity saving throw to avoid the spell.
\end{document}

\\
. Instead, just leave a blank line between paragraphs (or end them with\par
which essentially is the same). – Skillmon Jul 31 '17 at 12:47