Inserts that you can buy in stores without a prescription can provide cushioning and support. They may be made of materials like gel, plastic, or foam. Inserts fit into your shoes. But they're not custom-made for your feet. They can provide arch support or extra cushioning on the heel, around the toes, or for your entire foot. Inserts might make your shoes more comfortable but aren't designed to correct foot problems.
Orthotics are different. They are prescription medical devices that you wear inside your shoes to correct biomechanical foot issues such as problems with how you walk, stand, or run. They can also help with foot pain caused by medical conditions such as diabetes, plantar fasciitis, bursitis, and arthritis. Orthotics might even help you avoid surgery to fix flat feet.
Still, you might not need the prescription medical devices. Sometimes, an over-the-counter shoe insert will work just fine. You'll want to ask a podiatrist, a doctor specializing in foot care, for her recommendation.