Assuming you are talking about plastic glides on the bottom of furniture legs:
There are a few ways to remove these types of glides, depending on the type and how they are attached. The most common type is held on with a small metal pin or screw. To remove these, first use a pair of needle nose pliers to pull out the pin or unscrew the screw. You may need a small flat head screwdriver to help with this. Once the pin or screw is removed, the glide should come right off. If not, gently pry it off with the screwdriver.
Another type of plastic glide is held on with double-sided tape. These can be more difficult to remove and may damage your furniture if not done carefully. To remove these, first use a putty knife or other sharp object to loosen one edge of the glide. Then slowly peel it off, being careful not to tear or damage the surface of your furniture. If there is any adhesive residue left behind, you can remove this with rubbing alcohol or another solvent