Can I add custom fields to a single page? Sorry for another "In Wordpress..." question but here we go...

In Wordpress, I can use ACF to add custom fields to a single page. This is done either in code or in the GUI by basically doing something like (pseudocode),

if id = 123
  add_field "Phone Number"
end 


This is especially useful on homepages or landing pages where the layout is unique and I want to provide structured data entry without needing to create a custom type that is only used once. In Drupal, I dont see a way to dynamically add fields to an arbitrary piece of content. Is this possible? How?



Wordpress custom fields:
If you are using Drupal 8, you can create a block type and add fields to it. Then create a block of your block type and on visibility rules you can assign it to a specific page.


Video Tutorial.


If you're using Drupal 7, you can do the same, but you'll need the Bean module