My seo company has done well in grown much recently, however I am having trouble managing all my clients. In particular the billing, and expenses associated with each client. how are you doing it? Is there any software you are using? Optimally I would like to find a program which tracks the invoices and expenses and also, is integrated with some type of project manager where we could store documents and notes related to each client.
There are loads of paid and free billing and invoice scripts and apps, if you receive payment through paypal why not use there's? It's pretty thorough. You can search google for billing and invoice scripts, the paid ones are usually more secure.
Best option go for opensource myclientbase If you have website create a subdomain invoice and install the script there. So you can use it free and more convinent