I want to format the default style for text links—currently the color is blue & are underlined.
Is this possible? And if yes, how can I do it?
It does not appear to be possible to update the default style for links in your Google doc. This is because Google docs does not treat links as styles. This is understandable, as a link might be applied within text formatted with any other style (e.g., Heading 1, normal text, etc.)
If you try highlighting a link and checking the context menu, note that the option is given to Update 'Normal Text' to match. This indicates that the style of the text is designated exclusively as 'Normal Text' (i.e., does not have a link style).
Workaround to remove link underlines
I really wanted to be able to change the default for links in the body text to prevent them being underlined. I realise that underlining links is a usability plus online, but aesthetically I felt that it often ruined the flow of a body of text within a document. My workaround is as follows.
If you do not use underlines anywhere else*
This will remove underlines from all text in the document, including links.
If you want to retain underlines elsewhere (e.g., headings, tables)
This will remove underlines from all Normal Text, including links. You could alternatively use this to change the colour of links to the same as the body text, but you would have to leave the underlines in place, otherwise there would be no clue that the links were there.
I came across the same problem. All you need to do is alter the colour of the text the same way you would normal text.
Google doesn't seem to mind if it's a link or not.