How to change the color of a
PDF document.

Open your PDF document.
Click Edit, then click Preferences.
Click Accessibility.
Click Replace Document Colors.
Click the box to choose your color.
Click your color choice or add a custom color.
Choose to change the color of only those things that are black.
Choose to change the color of line art as well as text.
Click OK to apply these settings to your document.
VIOLA! You have changed the colors in your document!
You must repeat these steps to change back to black or the next document you open will have these same colors.

Here is the link to the FREE download shown in this tutorial:
https://thestampdoctor.com/wp-content/uploads/Recycle-This-Card-Saying-Colorable.pdf