Hello There!
Greetings of the day!
This is a part of the woocommerce template and to update the heading tag, you need to create a child theme that overwrites the current format.
Please follow below-mentioned steps
1) Go to eCommerce Gem Theme Directory
2) Go to ‘Includes’ Folder
3) Copy “woo-overrides.php” file,
4) Create a Child Theme
5) Create ‘Includes’ Folder in Child Theme
6) Paste the file (Copied in 3rd step) in created ‘Includes’ Folder
7) Replace “h2” to “h3” under “ecommerce_gem_woocommerce_template_loop_product_title” function.
Please have a look here in case you need more help in creating a child theme.
Hope this helps.
Thanks and Regards,
Team ProDesigns