What is a Digital Crown on a Apple Watch

M1 Mac mini, macOS 11.2.3; Watch, series 5 GPS/cellular, watchOS 7.3.3; iPad Pro 2nd Gen, iPadOS 14.4.2; iPad Air 2, iPadOS 14.4.2; iPhone 12 Pro, iOS 14.4.2; TV 4th Gen, tvOS 14.3  HomePods, audioOS 14.3 and Airport Express w/ Airplay 2

Its the big round nob on the side.

How to use your Apple Watch - Apple Support

So, which question do you need answered

You asked about the digital crown, but in the body of your post you need to reset your Watch.

So, which is it?