Yes! You can! Lets say your email address is username@gmail.com. You can reformat it by putting dots, for example u.s.er.name@gmail.com.

Google’s help centre explain:

Because Gmail doesn’t recognize dots as characters within usernames, adding or removing dots from a Gmail address won’t change the actual destination address. Messages sent to yourusername@gmail.com and y.o.u.r.u.s.e.r.n.a.m.e@gmail.com are all delivered to your Inbox, and only yours.

- Am I receiving someone else’s email?