I want a feature where on click of a button a meeting is added to user's outlook calender. I am using share point online so no managed code. WHat is the easier way?
At first you will need some information for the meeting: time, location,description etc. Where does this information comes from? Predefined or user related?
Another question would be: Where to place the button? At a page or within another form?
Without any information about my answers above I would suggest to check out Flow. It contains actions like create events in Outlook and it doesn´t require any coding skills. But Flow needs triggers to start the process. I suggest this could be the creation of an SharePoint list item where you can provide the information of the event.
The button could be a tile of the promoted links list, placed as web part on a page. The link of the tile would redirect to the new item form of the previously mentioned list. This would trigger the flow action and the event at outlook would be created.