WFH stands for "Work From Home" or "Working From Home". The word "Home" in the expression simply means "Not in the Office". Similar expressions "Working Remotely" or "Commuting Virtually" are also popular ways to avoid showing up to the office.
A remote workspace is created when you perform any function of your job in a spot that is not owned or leased by your company. Workspaces are measured in terms of quality, comfort, availability, and consistency. Preference varies greatly from person to person. Here are some examples of a remote workspaces: