Rerun cmp plugin on new file created or existing file change/rename

I’m working on nvim-cmp plugin, and I hit the wall. I need some way of watching existing files and watching for new created files and when this happened I need to rerun my cmp plugin. Is there any better way of doing this or autocmd is my friend? I would like to run only some functions not all plugin if is possible. Thanks in advance. :saluting_face: