A Gmail user can create a professional email signature with the help of free templates provided by their company, which range from simple and classic to more advanced formats that include booking links, social media embeds, product photo carousels, and GIF carousels. The templates cater to various industries, such as sales, retail, real estate, law, and design. To install a new signature, users can follow steps in the provided Google Doc, which includes copying the template, customizing it with their personal information, and saving changes. Additionally, tips are offered on how to avoid common email signature mistakes, such as including too much information, outdated disclaimers, or cluttering threads. The article also discusses automation options using Zapier to connect Gmail with favorite apps and automate workflows.