Research has shown that a one-size-fits-all approach to learning is the least effective educational method. Students are individuals, which means that they will have individualized approaches to the learning process that work best for them.
“Universal Design is the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design.”
Simply put, the goal for Universal Design is to simplify life by making products, communications and the built environment as usable as possible, by as many people as possible, at little or no cost. 
An example, would be to allow learners to express what they have learned in a variety of ways for assessment purposes, or in UDL terms, using multiple means of expression (MME). For example, instead of limiting learners to writing a paper on a particular topic, they can create a powerpoint presentation, or a wiki site, or a video instead. All assignments should have detailed marking rubrics to make sure that the learners are being held accountable to the same standards for the assignment despite the various means of expression.
 DeafTEC™, Technical Education Center for Deaf and Hard-of-Hearing Students
 Mace, Ron, The Center for Universal Design, North Carolina State University.
What Is Universal Design for Learning? from Rochester Institute of Technology