How To Use Your Headshot Online
For all of the below, you will need to save your headshot files to your device (computer or mobile device) first and remember where it is saved. In most cases you will want to use the square image file unless the place you use it can display a large photo - the rectangular image file is also much higher resolution.
Google/Gmail
On Google, you add your profile photo (use the square image file) via Gmail. Here is a good video: How to Add or Change Your Gmail Account Photo - YouTube
There are two ways to use your headshot on Facebook: your profile photo, and your cover photo. Usually you will use the square image file for your profile photo. This help topic shows you how: How do I add or change my profile picture? | Facebook Help Center ...
From Instagram help: How do I add a profile picture or change my current picture ...