The basic structure of a formal letter: The rules might be arbitrary, but taken together they create a formula that produces clarity. When a letter follows all the rules, the reader doesn’t have to struggle to figure out where a piece of information might be, what action they should take next, or who sent it _ everything can be found in its place. Knowing the rules of letter writing is, in that sense, akin to knowing the rules of page layout or web design _ the format of the document should support and clarify the content.
You can also include links to online portfolios, if appropriate, or a link to your professional social media account such as LinkedIn or Twitter. You don't want to make this section too cluttered, however, so restrict yourself to the most relevant information. Here's how to set up an email signature, along with more advice on what to include in it and what to leave off.