On published pages and pages in designer mode, you can access the source module for a card. All users with access to the page can access the source module. 

Use this option to learn the location of your data and engage with underlying data directly.

To edit cards, select Edit to open your page in designer mode.  

Select Save to save as a draft, or Publish to publish the page. 

To display the source module name, and then access the module for a card, hover over your card and select Card options , then select the module number under Source module.