I have two websites that doesn't have child themes. One

Hi,

I have two websites that doesn't have child themes. One is been running for several months and I realized now that I didn't install a child theme into it.

The other site the theme didn't come prepackaged with a child theme.

Is there a way to just install a plugin or something and it creates an instant child theme for the site like that?

Please advise.

Thank you,
Virgil