The $\mathrm{OH}$ group of an alcohol or the$\mathrm{COOH}$ group of a carboxylic acid can be replaced by $-\mathrm{Cl}$ using:

$\mathrm{PCl}_5$ on reaction with alcohol and carboxylic acid, replace $-\mathrm{OH}$ group with $-\mathrm{Cl}$. $$ \begin{aligned} \mathrm{ROH}+\mathrm{PCl}_5 \longrightarrow \mathrm{RCl} & +\mathrm{POCl}_3+\mathrm{HCl} \\ \mathrm{RCOOH}+\mathrm{PCl}_5 \longrightarrow & \mathrm{RCOCl}^2 \\ + & \mathrm{POCl}_3+\mathrm{HCl} \end{aligned} $$ Related Theory $\mathrm{PCl}_5$ is used as a chlorinating agent and dehydrating agent for the synthesis of pesticides, phosphite antioxidants, plasticizers and stabilizers for plastic and elastomers etc