I am in a pdf document and need to edit an existing link. I can successfully change the link and test the link. However, you know how links are displayed so that the link is underlined. Only part of my link is displayed in underline. How to I make the whole link show underlined?
The underline of a link is largely an HTML thing.
It helps provide visual focus for a link to the person visiting the web page.
Links to locations within a document or between documents are most often not underlined.
Very often such links are denoted by a color so as to visually identify the presence of a link associated with the specific text string.
Of course, one can establish color and underline in the authoring file.
These would appear in the output PDF.
The actual "link" functionality would have to be set via the authoring application (e.g., MS Word's Hypertext).
Once in the PDF, you can select the link annotation with the Link tool.
The annotation "box" shows. With the cursor in this box, right click to open the context menu.
Select "Properties".
In the Link Properties dialog, provided "Link Type" is selected to "Visible Rectangle", you can use the "Line Style" drop-down menu to select "Underline". Then use the "Color" setting to established a desired color.
If it is the text string itself that you want to have more underline for then, again, you'd do that in an authoring application for the source file from which you got the output PDF.
Be well...
Be well...