Wear a mask.
If you wear a mask, will it keep you from getting Covid-19? No... but
that's not why you wear a mask.
Most people who are infected with Covid-19 don't show any outward symptoms for the first few days, and some never show any outward symptoms at all. (I say "outward" symptoms because the virus still causes heart damage in approximately 70% of victims, even people who never show symptoms at all. The flu doesn't do that. Covid-19 is not "just a flu.") So, you could have Covid-19 in your system right now and have no idea. And if it's in your system, you're contagious -- even if you're not showing symptoms.
When you breathe out, moisture particles from your nose and mouth spray out six to ten feet from around your head -- possibly further depending on air currents around you. Anyone nearby who breathes in those particles can be infected too.
That's where masks come in. Put on a mask, and your six-foot spray radius becomes six inches. That makes it a LOT harder to you to spread the virus to others if you happen to have the virus but aren't showing any symptoms.
Ask yourself this: do you have Covid-19? Probably not... but unless you've been tested in the past day or two, you don't know for sure! You could have the virus right now and be contagious and EASILY have no idea.
So... wear a mask!