The free email permutations extension is a custom formula that generates permutations of emails based on three inputs: name, last name and domain. The formula works by taking the name and last name inputs and generating different combinations of these names. Then, it combines these combinations with the domain input to create all possible email permutations. The formula uses concatenation to combine the different combinations of name and last name, and the "@" symbol with the domain input to create the email permutations. Saves time: With this app, you can quickly generate all possible email permutations without having to manually input each combination. This can save you a lot of time, especially if you need to generate multiple permutations.