payment terms and conditions for my transport company

Hi i owe a transport company and i have a handful of customers that i do work for daily. When i complete jobs for them and i send the customers my invoice so that they can pay it, it takes them to long to pay me for the work i have already did for them. I would like to update my payment terms and if the customers do not pay my invoice in a specific time frame then an 5% interest charge would apply to the total of the invoice everyday that they are late. If there is a freelancer out there that has did a similar policy for a customer please let me know if you can do something like this for me