Shortcode for counter

Hello,

Is it possible to create an 7 days counter to use in our Form?
For example:

Every week we give away a 30 day membership.
Next winner will be picked in 4 days.

I have read this but I’m too newbie:
https://docs.mailpoet.com/article/63-hook-to-add-your-own-shortcode

Please help ??

Thank you guys!