WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture...
Use a test copy of your website, often called staging, in an environment separate from the live site. You can create it locally or in suitable hosting space. Restrict access, discourage search engine indexing, and disable automated messages, live payments and integrations that could change external data.
Before updating, keep a separate copy of the files and database, and check that restoration is possible. Test updates on the copy, then check key pages, forms and features. Apply only verified changes to the live site; do not replace its database with the test database if new orders, accounts or other data have arrived in the meantime.