To design meaningful interactivity into any learning form, an instructional designer considers the purpose of the interaction. Then they seek to alter learners’ behavior or skill level through that interaction; and then move learners closer to achieving their desired objectives by internalizing the information learned within the interaction. This is what it means to build meaningful interaction.
Interactivity in eLearning has four different levels:
1) Simple interactive experiences, like clicking or tapping to reveal some information,
2) Selecting among basic available options,
3) More advanced interactive problem solving 
4) Creation of complex interactive elements 
Experienced instructional designers employ all these types of interactivity in varying areas for varying reasons. Simple interactivity is an excellent place to begin a course. By having learners make fun and simple choices at the beginning of the course, we help them develop confidence in their early achievements building motivation. Then, as the learner progresses through the course and more complex interactions are introduced; their confidence serves them at the next level of interaction.
Meaningful interactivity steers the learner towards achieving the learning objectives; whether the objective is a simple information recall; or is more complex and involves altering the learners’ decision-making process . That is why the complexity of the interactions depends on both the objectives of the course and the complexity of the expected outcome. Though it is easy to imagine all the wonderous things that can be used interactively to push learning forward, there will always be a place for the simplest of interactions in all eLearning.