Size guide add-on allows you to assign ready-to-use default size chart templates to the product page
You can navigate to Woostify Options and enable this add-on.
Then go to Size guides -> Add new to create a size chart template. You can enable a page builder like Elementor to create a perfect size chart.
Then you need to set this size chart to apply it to the products you want.
The last step is to Update to save your size guides.
In the product description, a small button “Size guides” will appear so you can click it to get the size chart.
Here is the video tutorial of Size guide. You can watch it for more details.