Online sign link in pfd

Hello
i added online sign link in the pdf like this

Online Sign: <span style="font-size:4px"><em>__ONLINE_SIGN_URL__</em></span><br />&nbsp;
the result like this

https://mydomain.com/public/onlinesign/newonlinesign.php?source=proposal&ref=PR2412-0250&securekey=$2y$11$9rC16Ygy/BxTiLdWIsCtJ.WkPqXEDE3/i5K12MFdcoPifrvAvrj9y

i make the font size 4 because no warping and bigger font create 2 lines which give bad address
is there away to make online sign link shorter or clickable icon in the pdf