There are many digital online pdf editors around. I'm using pdf escape because that's what I am used to. Pdf Escape is a free online pdf editor and form filler.
Below is a step by step tutorial on how to blanco a document using an online pdf editor like this one.
Go to Pdf Escape.
Step 1: Click on the "Free Online" button
Step 2: Click on the Upload PDF to PDFescape link.
Step 3: You can either drag and drop your file from your desktop to the box or click on choose file to find the filename from your saved pdf document and then click on the upload button.
Step 4: Click on the Whiteout Tool Button. (This image shows the document "before" you edit).
Step 5: Click, drag and release your mouse on all the places you wish to "blanco". (This image shows the document "after" you edit)
Step 6: Finally, click on the icons on the left to download or print.
Of course a pdf editor can do a lot more other than just to "blanco" a document. However this post will touch only on this aspect of it. You can play around and test the other features when you are working with your document. Another interesting use is when someone sends you an empty form. You can use the editor to fill up or complete the form and share the completed form with the sender digitally.