Here's how to export your list of customers from ContractorTools:
Select "Company Settings" from the main menu.
Scroll down to "Export Customers" and select it.
Tap (or click) on "Export Customers"
This will display the "share to" popup on your iPhone or iPad, or the Save dialog box on your Mac, where you can indicate where you want to send or store the file.
The list of customers will be exported to a .csv file which can be opened in Numbers or Excel, or imported into email systems such as Mail Chimp, or CRM systems.