Young adult learners have a great instinct or capacity to conduct tasks for different purposes. In order to convey our thoughts or messages we all need to have effective writing skills. The aim of the current study is to help and improve writing skills of young adult learners by using a portfolio including different tasks. At the beginning of the study, interviews with teachers and pre-questionnaires with students were applied for their ideas about the problems in English learning. At the end, students had post-questionnaires to express their ideas on the role of portfolio usage. Another goal of this study is to make young adult learners use English effectively by improving their pronunciation, the use of language, spelling, punctuation and grammar. Sixty high school students who were in AA and AB classes and whose ages were between fourteen and fifteen .The duration took nearly six weeks. As a result, we have found that the young adult learners have boosted their vocabulary, critical and creative thinking as well as, analyzing, reasoning, deducing, self-awareness skills.