How to Add Comments and Draw / Write directly on a PDF Document
This article provides some basic instructions of how to add text and signatures to an existing PDF formatted document, using the Free version Adobe Acrobat Reader DC
Fill & Sign Feature
1. Open the document in Adobe Acrobat Reader DC
2. Then select Comment from the pane on the right
Ribbon Selection
3. Then select from the available tool ribbon.
4. Then place your cursor where you want to add your comment. Depending on which tool you chose to use, by the click of your mouse on the document, either a text box will be created on top of the document or you are able to mark directly on the document.
5. If you chose a text box, when you are done entering text in that section, click outside of the text box and it will close. You are now ready to select a different comment tool from the ribbon above or continue with the one you were using to add another comment to a different area of the document.
Directly Drawing / Writing on the document
6. To draw directly on the document as if writing with a pen, select the "draw free form" tool from the selection ribbon towards the center of the above Header.
7. To change the color of the "ink", select the "color picker" icon and make your changes.
8. To change the width of the stroke, select the "line thickness" icon from the tools ribbon. Then make your adjustment.
9. Then you can draw directly on the document using a stylus or your mouse by holding the left key down and dragging the mouse.
Save Edits and Back out to Read Only
6. When you are done SAVE your document by selecting the Disc icon on the top left of the screen.
Alternatively you can select to go Back to Document which will take you out of any editing features.
(you will still need to Save the document to retain all changes/marks you made)
Here are some additional articles that can help.
https://helpx.adobe.com/reader.html
https://helpx.adobe.com/reader/using/fill-and-sign.html
Other Help tools https://helpx.adobe.com/support/reader.html
With 8192 levels of pressure a perfect Stylus Pad to use for e-signatures is produced by XP-Pen https://www.xp-pen.com/
There are two sizes that are ideal for the purposes of document signing
XP-Pen G430S 4 x 3 inch
XP-Pen StarG640 6 x 4 Inch
Both are Ultrathin Drawing Digital Graphics Tablets with Battery-free Stylus (8192 levels pressure), USB connection and virtually plug-n-play, however there is a driver that can be installed for more functionality and control.
These models can be found relatively inexpensive between $20-$30 on Amazon, just search up the model name as suppliers tend to change.