An asterisk (*) in a Gmail email address indicates that the email alias is configured as a catch-all address for the domain. 

Gmail users can also create aliases for different purposes by adding a plus sign (+) and any word or combination of characters after the username. For example, if a user's email address is janedoe@gmail.com, they can create aliases such as:

• janedoe+friends@gmail.com for personal matters
• janedoe+work@gmail.com for professional communications
• janedoe+banking@gmail.com for finances
• janedoe+shopping@gmail.com for online purchases
• janedoe+subscriptions@gmail.com for recurring paid services 

Users can also modify their Gmail address by inserting one or more dots (.) anywhere in the email address. Gmail does not recognize periods as characters in addresses.