Can we generate the following reports by Forma LMS:
1) No of Trainings attended by user/students on Monthly Basis.
2) Absenteeism Report of user/students on monthly basis on various training.
3) Assessment reports of users/students
4) Can we set the Reminder email to students before any training starts on a particular way such as:
i) One Week before
ii) 3 days before
iii) On the Same day just before the training starts.
all reports are "custom", since you can create user reports, course reports and aggregated reports. Just try to use the report function creating a new report and you'll easily see that.
You can relate users to courses, make delay analysis, relate users to LO's or to communications or contests.
And in the end you can choose to link users to one or more courses and to display whatever kind of information is available.
Automatic reminders are a different story: from the report (from any report) you can select users and send them an e-mail with the frequency you wish.
The kind of automation you're asking for is not natively included in Forma, custom development would be necessary. The way you are describing it, I would relate those reminder e-mails to courses and have them be configured in the course settings.