shanebp

BuddyMessageUX-Free is a BuddyPress plugin.
Default behavior for the buttons is to take you to your own profile – to compose and send messages from there. 
Why? Why not stay on the profile page you are viewing?
Fortunately, BuddyPress makes it easy to replace the functionality for those buttons. 
With this plugin you can stay on a profile page and send private or public messages to that member.
This plugin uses the default WordPress ‘thickbox’ code.
If you need… 
* the ability to style the overlay 
* adjust the javascript 
* or prefer the use of ajax
… you might be interested in the premium version here: 
<a href="https://www.philopress.com/products/buddymessageux/" rel="nofollow ugc">PhiloPress</a>

BuddyProfileMessageUX Free

This BuddyPress plugin replaces the functionality for the Public Message and Private Message buttons on profile pages.

Dreb Bitanghol

This field will provide you more options and flexibility on how you would like to present an instruction or message to your client’s (or site in general) admin interface.
Features:
<ul>
<li>Support PHP.</li>
<li>Option to hide label when field is displayed.</li>
</ul>
Compatible with Advanced Custom Fields:
<ul>
<li>4 (tested up to 4.4.6)</li>
<li>5 (PRO, tested up to 5.3.7)</li>
</ul>
PS: You need <a href="https://wordpress.org/plugins/advanced-custom-fields/" rel="ugc">Advanced Custom Fields</a> installed to use this.
PPS: Even more awesome if you have <a href="http://www.advancedcustomfields.com/pro/" rel="nofollow ugc">Advanced Custom Fields PRO</a> installed.
Important note: Use this with utmost care.

ACF Enhanced Message Field

Exactly what I needed

Exactly what I needed. You could improve the plugin by making the textarea field look more like an IDE, with system fonts, syntax highlights and so on.

Perfect

Awesome!!

Adds an enhanced version of the default Message field to accept PHP and certainly no wpauto().

BuddyProfileMessageUX Free vs ACF Enhanced Message Field