What software are you using? I don't think there is a 'universal' SIP account manager software, it would be dependent on what PBX system you're running (e.g. Axon, Asterisk, 3CX, etc.)
Axon has a built-in web server so it can be controlled locally or remotely through an easy to use web interface. The interface allows control of all aspects of PBX from account management, to dial plans, to call routing, logs, and more.
Here are a couple of a screenshots:
