How to Solve Duplicate URLS?

Hi,

I'm currently auditing a site and noticed that they have a few duplicate urls.

For example there would be two similar urls which the only difference is a "/" at the end or the url will be in capitals. These pages have the exact same content.

For example one URL will look like this:

example,com/help/ vs example,com/help

example,com/Help vs example,com/help

I'm just wondering what should I do with these duplicate urls. Should I do a 301 redirect to the preferred URL or add canonical tags to them?