When we are creating text materials, in any format (digitally or printed), we need to consider the three major principles of the Universal Design for Learning (UDL)
Representation: designers and instructors should provide information in multiple formats for learners — audio, video, interactive text so learners can access content in a manner they like based on their learning style and strengths.
Action and expression: designers and instructors should create multiple pathways for learners to engage with materials and various options (choice) in demonstrating an understanding of new knowledge, skills, and abilities.
Engagement: designers and instructors should infuse multiple ways to motivate learners, such as providing voice and choice Voice in what and how content is studied to build interest and choice in approach and demonstration of understanding.
Beside the UDL it is important to consider the 5 elements of the Visual Design which are: Contrast, Repetition, Alignment, Proximity, and Simplicity. Below is an example of Infographic for a digital citizenship lesson for middle and high school students.