ACTIVE LOUDSPEAKERS

USB-C accessories and cables will work with a Thunderbolt 3 port. All Thunderbolt 3 ports are also USB-C ports, using the same style connector. I don't have any experience connecting to amplified speakers but I'm guessing that what you'd need would be a DAC with USB input to take the signal from the Macbook, convert it to analog and then on to the active speakers using a standard pair of analog cables, either RCA or AES, depending on what the DAC and active speakers have.
But, as I said, I don't have any direct experience with this so please confirm elsewhere.

Okay, I'm not shouting now, sorry about that. And secondly I was WRONG about the lightning connectors sorry agin. Okay the inputs and outputs are Thunderbolt 3's.The computer is The MacBrook Pro 15" screen and the year is 2016. I guess I'm looking for an AES-3 female to a Thunderbolt 3 male adapter. I can not find one can anyone?

Oh, and if what you're trying to do is play music from the MacBook to the active speakers what you want on the Macbook is an output port, not an input. It would be helpful if you would list the specific model of the Macbook Pro. You can find that under "About this Mac", the first item under the Apple symbol at the top left of the screen. In any case, all MacBooks have some generation of USB output so you can proceed from there using auxinput's advice above.

Please clarify. The MacBook Pro doesn't have any Lightning inputs. Depending on the model it has Thunderbolt and/or various versions of USB input. The iPhone and iPad have Lightning ports.

I would suggest getting an adapter that adds a USB port to your Macbook Pro.  I don't know enough to suggest something, so I recommend going to your local Apple store or Best Buy to have them help you in getting an adapter.

Once you have this, there are several computer speakers you can choose from that have USB inputs (check out Best Buy).  Or there are a couple studio monitors available that have USB input:

Behringer Studio 50USB  - typically $150
Alesis M1 Active 320 USB - $75-100 used on ebay

If you want something better than these, then look for a USB DAC, optionally with a volume control, such as Parasound Zdac or something similar.  Then you can choose any powered studio monitor from a pro audio company (such as Yamaha HS5 / HS8, or Adam a7x, etc. etc.).

Why are you shouting at us?