Hi,
Here's a brief introduction of each product (not so accurate to official documents, but general for product choice):
Microsoft Intune - Online management tool for Android, Mac, iPad and Windows computers, focusing on device management and application management.
Microsoft Configuration Manager - On-premises management tool, including application management, as well as OSD (Operating System Deployment), supporting PXE network boot. It can work with Intune to accomplish co-management.
Operations Manager - this is monitoring tool, to monitor the server, service, etc. is healthy or not. Its competitor is Nagios or Zabbix. It is mostly for monitoring windows and Unix/Linux servers. When something is wrong, it will generate alerts and send out notification to reduce the downtime and find out potential weakness, such as server workloads, disk usage, etc.
Orchestrator - automation tool to coordinate Operations Manager, Service Manager, Configuration Manager, etc. Most of the console task in each product can be automated in Orchestrator.
Service Manager - a portal to allow organization to manage incidents and problems, that is, we can submit requests in Service Manager, after receiving the request, Orchestrator will work with other products to fulfill this.
Data Protection Manager - generally, this is for backup your data.
If you only want to manager applications and device, then Intune and Configuration Manager is the choice. Intune is the lightweight one and cloud based. And Configuration Manager is the on-premises counterparts, which is more complex than Intune.
Regards,