Child theme – Multisite

It’s the same as single site WP. Just be sure to network activate both the child and its parent.
https://developer.www.ads-software.com/themes/advanced-topics/child-themes/

I learned this early on…

On my multisites I keep a child theme generator plugin installed and use that to generate the child themes… That provides a child theme that should be usable ‘out of the box’!

https://www.ads-software.com/plugins/child-theme-configurator/

If the child is created for a specific multisite. I’ll place something in the Child theme’s actual name to denote that. That’s to keep me or anyone else from accidentally enabling the theme on the wrong website.

If you have a lot of users on the site you might need to control the access to the child theme plugin itself and the child themes by way of the network admin settings for network enabling plugins and themes.