This is an interesting question that I get a lot in my practice. From an Akashic Records perspective we have different levels of closeness with other souls, just like we have close relationships here on this lifetime (mother, father, siblings, etc) we also have a version of that level of closeness at the soul level.

Ever heard of the saying "we are spiritual beings having a  human experience?" well, this is the reason why we have a "soul expression" for all of our interpersonal relationships, regardless if they are short lived or not on this lifetime.

So what does that have to do with Twin Flames or Soul Mates? you may ask.... well, the difference between both relationships is basically how close that soul is to you in respect to where you are currently as a soul, literally they are right next to you. 

Imagine yourself expressed as pure light, as a soul and that you live inside a gated neighborhood, and inside that neighborhood, there are houses that have several rooms, inside the room you reside, there are other souls, those inside the same room you live in are your Twin Flames (yes, you can have more than one) vs your Soulmate, is basically a soul that lives a couple of neighborhoods down the road!

The reason why the Twin Flame is so important is that this soul is directly related to your ascension as a soul, when this soul shows up in your life, they are going to move and shake all the karmic noise that you have been carrying all along and basically ignite you into healing and karmic release.

In contrast a Soulmate may not have as many karmic entanglements with you and you may have a rather peaceful relationship with them from the start, this doesn't mean that you may not have to work through some karma with your Soulmate, but the energy is not as intense as a Twin Flame will be.

This is why I always tell my clients that come to me for relationship clearings that we will also check their soul relationship with their loved one so that we can uncover any karmic energies that could potentially be at play there.

What in your own experience do you feel is the difference between your Soulmates and Twin Flame?