People can't edit your repl, however they can make a copy and edit the copy

If you mean you don't want people to see the code, you can use the repl.run link. However people can still find the code by searching your name on repl.it.
If you don't want people to be able to edit the repl but see the code, you can do that by sharing the repl link. When people try to edit, they will fork the repl, and no changes will be made on your repl.
If you don't want people to see the code at all even if they search your profile, you can use private repls which are only available to people who bought the hacker plan.

You could just give them the run link, maybe?