Input enhancement's role to promote learners’ awareness in L2 contexts has caused a tremendous amount of research. Conspicuously, by regarding all aspects of input enhancement, the study aimed to find out how differently many kinds of input enhancement factors such as bolding, underlining, and capitalizing impact on L2 learners’ vocabulary acquiring. Furthermore, the study was conducted through a quasi-experimental design with a proficiency test to find how homogeneous the groups are. Four classes were selected as the experimental groups (n =80), and each class was conducted by one of the input enhancement main categories compared with the control group. Subjects attended in eight sessions to make them familiar with advantages of input enhancement in relation to vocabulary learning. Each group received different strategies but control group received no treatment and then, the researcher taught and employed those inputs in texts along with target words. Learners’ progress was measured during the eight sessions of employing those inputs in responding to vocabulary questions. One-Sample Kolmogorov-Smirnov Test, One-way ANOVAs series along with LSD and post hoc comparisons showed that three inputs were effective in responding to target vocabulary words and they compared and contrasted with control group but the bolding group did better than the other groups. Finally, bolding target words were more effective in fostering L2 learners’ vocabulary knowledge learning. These outcomes propose that using input enhancement to answer target words are the most useful factors, especially bolding as a significant input in this study outperformed the other ones in developing learners’ awareness to answer vocabulary tests. It can also be concluded that capitalizing is the least effective input compared to underlining and bolding in terms of their efficacy. Keywords: Focus on form and Implicit Fonf, Input enhancement as focus on form, Vocabulary