Hello,

We have the 3 plants shown in the attached pictures in our house. We would like to know how we can get them to grow and thrive.

Dracaena marginata, looking as they typically do indoors, the way most people care for them.
They would hold more leaves if they got more light.
They normally never branch out or become fuller, the way shrubs in the landscape look. They grow from the tips. They hold as many leaves as conditions allow.
The potting may not be ideal, we cannot judge that without t more information. But I think light is the limiting factor.

Agree that they need more light and we need more information and better photos.

They all look too low in the pots, which restricts airflow. Are they in smaller pots inside those large decorative pots? Do they have drainage? How do you water, do you fertilize?

Open the blinds.

What is the orientation of that window or glass door?
If it were mine I would position the plant right infront of the window, especially if it is a north facing or east facing orientation. You have to open the blinds some more, got to let some light come in. I would also put that container on some sort of platform with wheels, that way you can do some quarter turns a few weeks at a time, to even out light distribution.

If you do not wish to move the plant from that corner, consider either putting a mirror behind it to bounce off some light or use some grow lights.

Also be mindful of watering, Dracaena marginata indoors prefers to be on the drier side.

Thank you all for your answers!

We are west facing. The plants sit lower and are in smaller pots in the decorative ones. They do have drainage and we water when they are dry. There is no fertilizer.