It's all about celebrating your LOVE!
Doesn't matter how you call it... engagement/couples/pre-wedding session, it still celebrates one... YOUR LOVE!
But what is the difference between the three named sessions? Well, let me tell you.
Your engagement session could be secretly booked for me to capture the engagement happening. This is one of those where I would hide or pretend that it's just a couples photoshoot but in reality, one partner is going to propose and it's only two of us that know this secret.
A pre-wedding session and it says in the name, a session done before the wedding. This is great for you to get a good feel in front of a camera, practice some poses and for us to meet in person (if we haven't by then).
Last but not least is a couples session, this is for anyone who wants to have their photographs as a couple but might not be engaged yet. Simply a celebration of love!