This question has certainly already been asked, but I couldn't find it, using the site search function.
<i><a href="...">blah blah</a></i>
or
<a href="..."><i>blah blah</i></a>
To me, this is the first, which is the right one. Isn't it?
not2easy
12:05 am on Oct 18, 2019 (gmt 0)
Or there's
a.ital{font-style:italic;}
<a class="ital" href="...">blah blah</a>
lucy24
2:08 am on Oct 18, 2019 (gmt 0)
Or there's ... class="ital"
For a total of 13 bytes (15 if you're generous with spaces, as I am), while <i></i> is seven :)
Between <a><i> and <i><a> there's no absolute right and wrong, though it's worth nothing that <a> can now be block-level (in HTML <= 4 it wasn't supposed to be, though browsers didn't mind) while <i> is strictly inline. Generally you'd want to put inline elements inside of block-level elements.
Use whichever one seems right to you. I, personally, have done both, as the occasion warrants--often within the same document--and also plenty of variations on not2easy's approach. The only absolute no-no is interlocking tags, like <a blahblah><i>blahblah</a></i>; that will make any validator kick up a fuss.