With modern technological advancements, the rise of digital learning has helped teachers and students in many ways; for example, learning is becoming increasingly learner centric. In recent years, learning has been compromised because of school suspensions due to the COVID-19 pandemic. Digital learning has helped to reduce the negative impacts on students' learning, and most students have shown a positive attitude toward digital learning. A learning management system provides a platform for learners to learn and interact with teachers or peers without time and space constraints. Moodle is one of the most popular and widely-used learning management systems. It is open source, offers different functional modules, and is available free of charge. However, according to recent literature, Moodle has several disadvantages. First, the topics discussed by students in the Moodle platform are not focused enough and not easy to be discussed in depth. Second, the interaction is not immediate because of a lack of instant notifications. Third, the interface is not user friendly and is thus difficult to operate. These drawbacks can hinder students' learning. Office 365 is another digital system that assists students' learning. Various functions of Office 365, such as Teams's real-time notifications and OneNote's recording function, complement Moodle. This study investigated the effects of after-school activities conducted through different media on students' motivation, learning achievement, and peer interaction. In present study, after-school activities were conducted face-to-face or via two learning platforms, Moodle and Office 365; the learning platform was considered the independent variables. In total, 143 middle school students were recruited as participants for an after-school activity and distributed into the face-to-face, Moodle, or Office 365 group. The quantitative data of three scales concerning with learning motivation, learning achievement and peer interaction were collected to represent their learning performance. Qualitative data were collected through textual analysis based on student responses to open-ended questions. The quantitative and qualitative data were then statistically analyzed with SPSS Statistics 23. The results of the quantitative analysis revealed the following results: (1) No significant difference was observed in learning motivation among the different groups. The reasons for the result may be that students were not familiar with learning management systems, the interface and function of the learning systems were complex, or student motivation to learn English was low. (2) The learning achievement of the face-to-face group was significantly higher than that of the Office 365 group. Office 365 has many functions, but it also increases the cognitive load on students. Additionally, middle school students in Taiwan are inexperienced with using learning management systems because of the lack of opportunities to do so. Furthermore, the focus of this research was not the formal school curriculum but after-school activities; therefore, gauging learning effectiveness was challenging. Finally, students are more familiar with face-to-face discussions, and this comfort increases the effectiveness of this mode of learning. (3) Students in the Office 365 group had a higher tendency to interact with peers than those in the face-to-face group. Interacting through Office 365 (as it provides voice and text input for discussions) removes the stress of public speaking, such as that experienced in face-to-face classes, thus increasing participation. However, the peer interaction in the Office 365 group was not significantly higher than that in the Moodle group because the students using Office 365 mainly used text input, which decreased the efficiency of their discussion. (4) Some groups of students using the learning management system (no matter Moodle group or Office 365 group) posted the answers to assignments in the chat room even before much group discussion, or they divided the work among themselves, and not discussing the assignment at all. The students seemed to be unfamiliar with the way in which group discussions are conducted through digital learning platforms. This inexperience was reflected in their lack of teamwork. (5) The ratio of discussions students posted on the Moodle platform (Moodle group) was positively correlated with their learning achievement and interaction with peers. The ratio of discussions students posted on the Office 365 platform (Office 365 group) was positively correlated with their learning achievement and learning motivation. The results have several implications. First, teachers should consider the most appropriate form of discussion for middle school students when planning group discussion activities during and after lessons. Second, although middle school students are better at learning through face-to-face discussion, the demand for distance learning and the use of digital platforms are increasing. Teachers should encourage the use of digital platforms by planning more exercises to implement through these platforms, thus improving students' learning performance as well as their efficiency in using these platforms. Third, the students in the Office 365 group had a higher tendency to interact with peers than did those in the face-to-face group. Thus, teacher may use Office 365 initially to make students willing to use digital platforms and for them to get familiar with its usage. Once students are comfortable using the platform, teachers can shift the focus to enhancing the effectiveness of learning. Fourth, when students are engaged in group discussions in after-school activities, only a limited number of students may participate, or students may directly provide answers without discussing them with their peers. Providing students with instructions and training on conducting group discussions may help them make more effective use of learning management systems. Finally, regarding the design of learning management systems, the registration and login procedures should be simplified, and the platform interface and operating functions should be more effectively integrated to make them user friendly. Doing so may enable novices to start and consistently use these systems more easily and reduce the time required by users to familiarize themselves with such systems.