PDF Reader provides the text editing tool that enables you to replace the text size and color.   

Change Text Size & Color:

1. Open the PDF. Click "Edit" > "Edit Text" to switch to the text editing mode.

2. Drag the cursor over the text you want to modify to select it.

3. Click the "text size" button, and you can change the font size.

4. To change the text color, click the "text color" button to change the text color for the selected text.

5. Then click "Save as" on the top of the page to save the changes.