All hair extensions work by attaching to your natural hair near the roots, but they attach in different ways.
The main extension types work with these application methods:
Clip-ins are attached to snap-on clips that go underneath your top hair layers. Inserting and removing them is easy.
Tape-ins adhere to your natural hair near your roots, and stylists sandwich them in between layers of your hair to make a strong bond. The adhesives on some tapes require heat to activate.
Sewn-in extensions are stitched into tiny cornrow braids of your natural hair (under the top layers) using a needle and nylon thread.
Fusion types & glue-ins are real human hair pieces attached to small sections of hair under the top layers with adhesives that last for months.