Welcome to UX StackExchange, Óscar!
What platform are you targeting? If it's an OS-native app, always honor the date format that the user chooses in their device's settings.
If it's a web app, though, who will be your users?
If you're sure that "every" user will be a US American, you can safely use the MM/DD/YYYY format. It's what everyone uses in ...
Each format has its pros and cons.
Nov 20, 2020
Requires less interpretation; better readability.
Not as easy to compare multiple dates.
Easy to compare with other dates to calculate durations.
For example, how many months apart are 2/1/2020 and 8/1/2020?
Easier to calculate than "Feb 1, 2020" ...