Can I get a Covid-19 vaccine (or booster shot) and a flu shot at the same time?

My friend is getting a 2nd dose of Covid 19 vaccine but after a week, she will also be getting a flu shot. Is that ok mommies? I got my Covid 19 vaccine last May and flu shot this September. It was a go from my OB but I wonder if ok with my friend’s case. Any thoughts?