I'm sorry but you're going to have to be more specific. Generally speaking if they are tropical or sub-tropical plants they may survive indoors but most other plants would be better outdoors with winter protection or in a garage, crawl-space, or basement where the will stay cold and dormant through winter.
I agree with Plantfeak and would also need to have the name/type of tree's or plants you are trying to keep inside for winter,
Most perennial plants die down beginning Autumn and are completely under the ground out of site by early winter therefore could be covered with about 3-4 inches of compost / leaf-mould over the soil around the root area and will be fine with that. come early spring/ around April, new shoots would be noted and the growing season would start all over again and end of season you would repeat the end of season preparation for winter all over again.
As for tree's / shrubs, again depending on tenderness of the type your growing, IF they are common to your area/climate then the prep is as for the perennials with the exception, the top growth will remain and NOT be cut back when the temps are falling, but laying compost/ leaf-mould around the roots a few inches deep will help protect young roots, the leaves will drop but if really concerned, then make a bag using horticultural fleece to drape over the trees IF SMALL enough to do this job, the fleece allows light onto the branches BUT gives a small amount of protection from freeze or night frost IF that would be enough depending on the plants you want to protect.
You would have to tell us what the plants are but I give general info for plants that are already able to grow in your local.