The default types for links and destinations can be set with the following commands:
\hltype{type}
\hldesttype{type}
where type is one of the link/destination types supported by the selected hyperlink driver (see Hyperlink drivers).
Default values for the options can be set with the following commands:
\hlopts{options}
\hldestopts{options}
where options is a comma-separated list of option assignments in the format ‘option=value’. Again, what options are allowed depends on the selected hyperlink driver.
Many people regard the default boxed links as not aesthetic and
intruding on page layout. The reason why boxed links are the default is
that the links are not colored until you load the LaTeX
`color' package (see Loading LaTeX packages) or use other means to
define the \color command; therefore, not producing any kind of
link border may result in the links not being marked in any way.
However, when the links are actually colored, there is no need to
produce the link boxes anymore; to avoid the boxes, you can set the
default border width to zero (if the driver you use supports the link
option bwidth; see Hyperlink drivers):
\hlopts{bwidth=0}