Safari Browser
When I try to log on to iCloud.com/mail on my IPad I get a error messages your browser does not support this .? My IPad is 2013/2014 model.
Question marked as
What iOS version is it running? Settings->General->About->Version?
Also verify what model it is: Identify your iPad model - Apple Support
With that said, you should not need to access your email through the website. Your iCloud email is available directly in the default Mail App on the iPad if your iPad is signed in to iCloud in Settings.
Add an email account to your iPhone, iPad, or iPod touch - Apple Support