Does anyone know how to create a dev/stage Landing page url for testing purpose?
You mean a dev Landing Page *domain*? Sure, register a domain (a fully unique domain is recommended, like example-dev.com) and make pages.example-dev.com a CNAME to your *.mktoweb.com hostname. Then add the domain as a Domain Alias in Admin.
Hi Sanford, isn’t there a “stage” mode in every Marketo instance?
No... what functionality are you expecting that isn't accomplished via the method above?
Are you getting confused with a "sandbox" account (not sure if this is included in every instance anymore). A "sandbox" account allows you to conduct testing without it impacting your production environment. Unfortunately, the sandbox environment does not mirror your production environment - so you'll need to setup this environment separately from your production environment.
Thank you Dan. I couldn’t find where to access the sandbox account. Any thoughts?
If you're not paying for it, you don't have it.
Your admin would know. It requires a separate login. Usually, the admin login is "sandbox@domain.com"