Concatenate Custom Field Value & HTML Value

To display the_meta () after the ‘by author for’ text just needs a small change:

<p style="text-align:left;font-size:18px;margin-bottom:5px;"><span style="color: #000000;">By AUTHOR FOR</span> <?php the_meta (); ?></p>

However I’m not sure you want to use the_meta (), because all values get displayed, and in an unordered list. (Reference: the_meta.)

Instead you probably want get_post_meta, so:

<p style="text-align:left;font-size:18px;margin-bottom:5px;"><span style="color: #000000;">By AUTHOR FOR</span> <?php echo get_post_meta (get_the_ID (), 'my-author-meta-key', true); ?></p>

Replacing my-author-meta-key with your meta key name, obviously.