Texts are a group of letters which are printed or displayed in a particular style and size. In the course of the fast speed of technological development everywhere and expanding use of computer based instruction such as online courses, students spend more time on a computer screen than printed media. Texts have been the main element to convey messages. It has also been a significant component for learning. The main goal of this research is to measure the effects of font type and spacing of on screen text and its readability in improving and boosting the learner's ability to read easily, recall information, and enhance their reading speed and comprehension from on screen text with different topics. The readability of text on screens is necessary to ensure effective engagement in order to enhance the level of students' readability. For this purpose two font types were selected, Times New Roman (serif) and Verdana (san serif) for the respondents. Verdana was designed only for computer screens display. Readability test on a computer screen was conducted on 30 postgraduate students. Overall, the results showed that there was a significant difference between the readability of serif and san serif font type of on-screen display. The research findings suggest Verdana font type as a better choice in displaying long text for on-screen display.