What is the importance using references to other links in <ahref> tag ??

Answer 1

It allows you to turn plain text into links so you don't have an ugly long link visible on your page.

For example:
<p>Click <a href = 'www.example.com'>here</a> to go to my site!</p>

The above will hide your www.example.com link as "here" so when a user clicks "here" they will be taken to the link specified.

Answer 2

it is used to hide links