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# Can I use custom LaTeX macros, newcommands, and packages?


### Custom LaTeX macros and newcommands 

Yes, you can specify your favorite macros and add your favorite packages [(this is a list of LaTeX packages we support)](https://github.com/Authorea/LaTeXML/tree/master/lib/LaTeXML/Package) 

1. In Edit mode, click on **Edit Macros** in the toolbar, under Settings ⚙️
2. Then, in `header.tex` you can define your macros and packages. 

## Macros
For example, if you put this snippet in your header.tex:

```\newcommand{\msun}{\,\mathrm{M}_\odot}```
and then go back to your article and write in a LaTeX block Hello $\msun$, you will generate “Hello M⊙”.

## Packages
For example, if you put this snippet in your header.tex:
```\usepackage{siunitx}```
and then go back to the Main view and in a LaTeX block you can now type `\si{\meter}`  which will render as m.

## Export style specific commands
In the `header.tex` you can also specify some commands which are style specific and only modify the exported document. For example, if your export style file asks for a **corresponding address** in the form `\corraddress{XXX}`, you can include in the header.tex (in the right place --- look for the instructions), the following snippet which will produce a corresponding address box:
```\corraddress{Author One PhD, Department, Institution, City, State or Province, Postal Code, Country}```



|| **Read more**: [Can I use a custom LaTeX class file?](https://support.authorea.com/en-us/article/can-i-use-a-custom-latex-class-or-style-file-1trm9st/?1551114246289)