If you want to make a copy of an existing product, just open that product, click the three dots in the top right corner and select Copy Product. 

The following attributes will be copied to a new product:

However, some details are not copied and will have to be set for the new product:

Using Copy Product, you can quickly add multiple similar items to your menu or inventory. For example, if you have 10 top shelf flower products that all have the same pricing options and substitutions, you can set up one template, copy it 10 times, and then rename each new product.