Managing more than one company
You can hold as many companies as you like under one login and move between them without signing out. Plenty of people run a trading company and a property company this way.
They stay genuinely separate
Each company has its own books, its own VAT position, its own bank connections and its own people. Nothing pools, nothing is netted off, and a figure never wanders between them.
Your access level is set per company too. You can be the Workspace owner of one and have View only on another, which is how a director of somebody else's company usually ends up.
What it costs
A Business Pro subscription covers one company, so a second company is a second subscription. Being invited to somebody else's company costs you nothing, because they are paying for it.
Switching between them
Pick the company from the switcher and everything follows it: the books, the reports, the filings and the people. Financial IQ remembers the one you were last in, so you land where you left off.