Brake noise can come from wear, rust, hardware, debris, or something more serious. The useful first step is not guessing online. Tell the shop what the vehicle is doing.
Mention whether the sound is a squeal, grind, click, or scrape, and whether it happens while braking, turning, backing up, or driving normally.
If braking feels unsafe, do not wait for a convenient appointment. Call the shop and ask what the next sensible step should be.