i have a mak apple laptop that suddenly stop working and I does not turn on What should I do

Start with If your Mac doesn't turn on.

Read and follow each of its steps, including all the links within it, all the way through and including Step 4, which directs you to:

If your Mac starts up to a blank screen

Read and follow each of it steps also, all the way through and including the end, which takes you to:

"If you still need help, please contact Apple Support."