Hi,
openMAINT is primarily a system for managing the inventory of buildings and plants and for managing the scheduled maintenance (time and threshold) and the breakdown maintenance (ticket management with opening on a self-service portal and execution of workorders with a APP on smartphone or tablet).
You can register Company, Rent, Payment data (unfortunately, you can not set a default currency), etc, but there are no standard features to generating invoices, registering payments automatically, etc.
However, it is possible to configure all the features you need by using the mechanisms provided by the CMDBuild framework on which openMAINT is built: configuring new types of data cards, designing and importing new workflows, designing and importing new reports, configuring new dashboards, etc.
CMDBuild Team