You can have WordPress, plugins and themes update themselves.
Where
Open a site and go to Advanced → Auto Updates.
Each is a separate switch, and WordPress itself can be set to take minor updates only or every version including major ones.
What we would suggest
- Minor WordPress updates: on. These are mostly security fixes and are rarely disruptive.
- Major WordPress updates: your call. On a simple site, fine. On a complicated one, do it deliberately with a backup.
- Plugins: on for simple sites. If your site is a shop, or leans on a page-builder, updating deliberately is safer.
The trade-off, plainly
Automatic updates keep you patched without effort, but they can apply a change while you are not watching. Automatic updates plus regular backups is a good combination; automatic updates on their own, on a site you cannot afford to have wobble, is not.