Shuttering, also called formwork, is the temporary mould into which concrete is poured: plywood or steel plates for the faces, with props, spans and ties to hold them. In south India the slab supports are often called centering, and the whole job "centering and shuttering".
Good shuttering is in line and level, tight at the joints so slurry does not leak, strong enough for the wet concrete and workers, and oiled for clean release. Its cost depends a lot on how many times the material can be reused.
Removal, called de-shuttering or striking, must wait until the concrete is strong enough. Times differ for vertical faces, slab soffits and beam bottoms and depend on cement and weather, so follow the specification or the engineer’s instruction. Striking too early can cause sagging or cracks, so record the pour date and the planned striking date for each element.
