What tools help freelancers stay organized professionally?

[Btaliat]

There are many tools that will be needed by freelancers, each of the tools performing various functions. Some of the tools that can be needed by the freelancers include Trello, Notion, Slack and even Google Calendar. It is always of the best interest to have these tools and as well know how well to make use of them. For instance, Google calendar can be used to schedule your time and manage your plans well. What other tools do you know?