Low sofas can be difficult to rise out of if you have any injury or disability or are simply older and not too strong. Making a sofa higher off the floor is a problem you can solve by using commercial bed risers. However, there are other ways to elevate a sofa that may be less visible or more aesthetically pleasing. A sofa should work well for you so that you can enjoy the furniture.
Many sofas are made with detachable legs. These legs screw into the underside of the sofa using a standard-size bolt. Some sofa manufacturers produce several sofa legs that are similar in appearance but different in height. It is also possible to go to a local carpenter or metal shop and have custom-height legs made that match the shape and finish of the original legs. Home improvement stores also have sofa legs in various heights and styles. Find the height that works for your application.
A platform is a good way to elevate a sofa. Build the platform in the shape of a rectangular box in the height you prefer. Cover the platform with paint or padded fabric in a colour that works with the sofa. The platform will hold the weight of the sofa, and you can attach the sofa directly to the platform for extra security. This type of lift is inexpensive and will hold up over time.
Inexpensive cup-shaped bed lifts can be used to elevate a sofa if the sofa leg fits into the lift. These lifts are sold in sets of four at various heights, and since they are designed to hold the weight of a bed, they can also hold the weight of a sofa. Make sure the foot of the sofa sits securely in the cup. You can attach a skirt around the bottom of the sofa to hide the lifts. Use hook-and-loop tape, and select a fabric that coordinates with the sofa for the best appearance.
A twin-size wood or metal bed frame --- without wheels --- can be modified to fit the dimension of the sofa by reducing the width of the crossbars or by reducing the width of the wood frames. The bed frame can be bolted to the underside of the sofa, and a skirt can be attached to hide the frame. Often this type of frame has adjustable feet that allow you to raise or lower the height of the frame within a range. This will make a stable support for the couch.