Download and install the plugin TablePress to add tables functionality to your wordpress site.
TablePress has an extension that can add responsive behaviors to tables.
Read about it here and follow the instruction to download an extension plugin. Although it is marked as premium you can use it without paying.
To summarize the instructions, download the plugin extension and install and activate it like a regular plugin. Then change the shortcodes of the tables (in the pages) to [table id=123 responsive=collapse /] when the id is your table id.