The ideal time to send your invoice may vary from client to client, or on a project to project basis. Generally, you want to send your invoice when you know the client is satisfied with the work you’ve provided. Many freelancers like to follow a system across the board for every client to keep things simple—the busier you are, the more important this will become. Just keep in mind that when you’re starting out, there will be some trial and error involved in finding what works best for you.
Invoicing at the start of the engagement may not be well-received by all clients, especially if you don’t already have a relationship. However, in the case of a new client or large project, it isn’t unreasonable to require partial payment before your work is completed.
Invoicing upon completion of the project is common in freelance work and helps to foster a sense of trust between you and the client. As your relationships with clients develop, you may see your invoicing process adapt alongside them.