Hi! If the invoice does not get generated, it means that there is an error somewhere in your custom invoice.php.
As michael mentioned, you should preferably not put any customizations in your theme folder because they will get overwritten when your theme is updated.
Since you have 2 different problems, lets split the approach too ??
Step 0: I strongly recommend creating a child theme first. Enfold has documentation about this too: Using a Child Theme . This step is not required for debugging the issue though.
Step 1: Create the folder woocommerce/pdf/madame_ruvida in your (child) theme and copy the contents of the Simple template to this folder. Don’t make any changes yet. Can you select the new ‘madame_ruvia’ folder in the settings? Can you still create an invoice? Good! you have successfully created a custom template
Step 2: Make your customizations. If something goes wrong, post the customizations you made so we can review what’s wrong.
Ewout