How do I save my hibiscus plant during winter? It is about 2 feet tall

If it is in the ground you will have to dig it up and plant in a container suitable for the size of the rootball,spray the leaves down with horticultural oil,bring indoors and place in a sunny window.If in a pot, repot in the next size up and again spray the leaves with the oil and bring indoors

Where do you live? Is it a tropical version or the perennial that can take freezing weather in the northern regions? Is it in a pot or planted in the soil. This information is necessary to help you figure out what to do with your hibiscus plant.

You can bring it in, and put a grow light above it. Put the light on a timer.

Yes, bring it inside where it is warm and gets daylight. Keep watering it but don't let the roots stay wet all the time. It may drop it's leaves and stop flowering, but keep up the watering less frequently (it is resting). When the weather turns warm move it back outside in the sun, give it some fertilizer for blooming plants and it will leaf out again and start to bloom. Most hibiscus bloom best when the day length is shorter.