Changing the default text

Hey there,

I am building a site that will be in Cyrillic. In this relation, buttons as “Learn More”, “Comments” or “Post Comment” are simply not relevant.

In this relation, I need to edit the text in the code to Cyrillic.

I am using a child theme. In this relation, I can edit the code when doing an “Inspect” but this does not apply permanently but just for preview.

Where is the file that contains all the code I need so I can make the edits? Also, where should I put that file so the changes will sustain after a theme update? Should I copy and paste the file in my child theme folder? If yes, then how should I make the theme crawl for that file and not the original one?

Thanks!