Utility for software function design?

Hi guys! Sorry for the noob question…but I’m a noob (not totally, but definitely not a dev!). I have a white collar job and I’m working alongside a group of devs in order to create a CRM. I have to say they are a great team and they keep me involved to design all the functions needed. I am always trying to explain how things should be linked together, and I create handy flowcharts to explain myself better. Is there a tool you can suggest to go beyond flowcharts? I would like to sit down and design all the functions of the CRM linking all the pieces together in the quiet of my office (well, home office rn) so not to waste their time, but flowcharts or mindmaps feel they are not the right tool or process for this. Anything you can suggest? Thank you!