How do you add dates to your email notifications?

Hello,

Does anyone know how I can add a number of days to the order submitted date in the email notifications customer will receive? 

For instance, If order date is on March 15, 2020 and I would like to add 5 days, it will display March 20, 2020 to the customer.

I tried:

{order.submittedOn|date %B %e, %Y} + days(5)

But it doesnt seem work

Thanks