By default, your WooCommerce shop page is set to show 10 products. sometimes this does not fit with the layouts you have on your theme.
It looks like this, but you’d like it to show complete 3 or 4 rows.
You can easily change this by going to Settings -> Reading in your WordPress Dashboard and change the setting “Blog pages show at most” to display 8 or 12.
That will adjust the amount of products that display per page on your WooCommerce shop page.