Yes sure, you can start with a free mendix cloud environment, see also: https://www.mendix.com/pricing/
It depends on the capabilities of the other software. Can you expose Mendix data, so that another application can consume (and display) it? Yes.
If you added more detail to your question, I could give a less abstract answer.
I have a data on the cloud and I want to make an application to connect to my tenant and show the data ,the dashboards on the tenant and to display the alarms that are activated