In order for a customer to pay by check:
 

• Click top right of your admin panel then select Payments Settings
• Under the section Other Payment Options make sure Check is selected > Continue
• On the next page find the Check Configuration area
• With checks, you have the option of accepting them via the storefront, mobile devices, and/or over the phone as a phone order. ​
• In the WYSIWYG editor section, you can enter in the text to display on the order completed page. This will typically include instructions on where to send the check.

Orders placed by check will always go into "Pending" status. Once you receive the check in the mail and it's cleared, you can go into the order and change the status to "Approved."
You can also allow customers to pay with E-Checks. Like a regular check, E-Checks take between 3 to 5 business days to clear. In order to enable E-Checks, you simply click on the box beside "E-Check" in the Alternative Payments section when you access > Payment Settings.