If you would like someone to make changes to your WordPress site content without allowing full administration privileges then create an “editor” account for them.
Start by adding a new user account. Go to “Users” -> “Add New” in the dashboard navigation menu. There you will see all the requirements and options for adding a new user account.
Fill in the form and where you see the “Role” drop-down list at the bottom, select “Editor” (change it from the default “Subscriber”).
That’s it! Your new editor can create and edit content, hopefully without breaking anything. The WordPress Codex has the full list of permissions afforded to the “Editor” role.
Tip: WordPress will generate a strong password for the new user and this password can be emailed to them, so it’s probably a good idea to ask you new editor to log in and change it and keep the password in a safe place (i.e. not an email inbox).