It is likely that before using After Effects, you have tried another Adobe product such as Illustrator or Photoshop. If so, you will recognize the lock layers feature. If not, all you have to do is go to the Timeline and look at the area where the buttons to enable or disable the visibility of your layers are located, and the one that turns on or off the audio of your clips.
If you look closely at that same space, you will find an icon in the shape of a padlock. But what is its function, and what exactly is the purpose of locking layers in After Effects?
When you work with a lot of footage, text, shapes, or effects, sometimes you can end up moving objects and other layers without even realizing it until the very end.
That happens a lot and can be quite annoying, so if you want any particular element to stay in one place and not move through your working process, you'll need to lock the layer it's located on as follows:
Use this feature to reduce the chance of accidentally modifying settings, and remember that while locking a layer prevents it from being edited, selected, or even moved, it will still remain visible.