In general it is a bad idea to try and combine several of biblatex's \...cite commands into a single \newcommand. Commands defined like this often need extensive workarounds to properly handle pre- and postnotes (i.e. \cite[123]{sigfridsson}, \cite[Cf.][]{sigfridsson} and \cite[Cf.][223]{sigfridsson}). Furthermore, they usually have extreme problems when dealing with citations to multiple works (\cite{sigfridsson,worman}). Last but not least, citation commands defined like this can cause biblatex's citation tracker to get confused (this is mostly a theoretical worry, but I guess with enough ingenuity one could create an example where this is problematic).
New biblatex \...cite commands should always in almost all cases be defined via \DeclareCiteCommand.
In your case there is no need for that, however, since \mcite is essentially \textcite and \hcite is more or less \parencite assuming you use an author-year citation style.
\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[style=authoryear, backend=biber]{biblatex}
\addbibresource{biblatex-examples.bib}
\begin{document}
\cite{sigfridsson}
\textcite{sigfridsson}
\parencite{sigfridsson}
\printbibliography
\end{document}

biblatex, right? What exactly do\mciteand\hcitedo? What is wrong with the usual\textciteand\parencite? One obvious difference is the\textcolor{black}, why do you need that? – moewe May 04 '19 at 06:14\mciteand\hcitefrom the other question: Combining\citeauthorand\citeyearas done in\mciteand\hciteis usually ill-advised, since commands defined like this will have problems with multiple citations, don't properly support pre- and postnotes and can at worst mess up citation tracking features. The proper way to define new\...citemacros is most of the time via\DeclareCiteCommand. In this case, though, I would suspect there might be an even easier solution. But I'd need to know what the commands are supposed to do exactly. – moewe May 04 '19 at 06:16\textciteand\parencite? – moewe May 09 '19 at 07:38biblatex. – moewe May 09 '19 at 08:07