## 1 Introduction  
The accelerated evolution of mobile technology has created new opportunities for learning at work. With the advances in information technology, numerous companies have developed or subscribed to a full range of online office platforms from external organizations which offer a plethora of services that allow employees to receive learning and training. With well-designed online learning modules, companies could effortlessly provide their employees with high-quality learning content [1]. Thus, it is crucial to scrutinize employee perceptions of online learning since their acceptance of online learning modules can be shaped by their views on the design and management of learning [2]. Under certain circumstances, mandatory learning can cause employees to be rebellious. The success of online learning depends on an understanding of how users embrace technology [3] and the impact of this technology on all aspects of learning and education. Considering the number of mobile users and the increasing opportunities offered by mobile technologies, exploring the determinants of employee adoption and utilization of technologies in the workplace can be seen as critical. The process of technology adoption represents a continuous interaction between individuals and organizations. [PERSON] suggests that decision-makers' understanding of the issues affecting the use of a particular technology can enable them to consider these issues during the development phase [4]. Studies have delved into the intentions behind individuals' acceptance and use of new technology [5]. Technology acceptance refers to whether and why an individual adopts technology, while technology adoption refers to the continued use of technology [6]. Within online learning, intention pertains to the willingness to adopt and embrace new technologies for future educational processes [7]. Users have the autonomy to select the technology they prefer to utilize. Consequently, grasping the motivators behind these choices can significantly contribute to crafting pragmatically applicable technologies [8]. Increased acceptance of technology-related issues indicates individuals' readiness to adapt their lifestyles to incorporate innovations [9], serving as a critical factor in the success of technological advancements [10]. Relatively, lack of acceptance may lead to technological failure and loss [11]. Following the outbreak of COVID-19 in 2019, numerous companies have developed and utilized online learning and training modules based on the online office model to promote the further development of their employees [12]. Therefore, the primary goal of this research is to investigate the determinants influencing employees' intentions to utilize online modules within office applications, aiming to foster sustainable learning within organizations. In this study, the online learning module is outlined as a training and education technology framework provided by the company and developed on an integrated office platform. In comparison to traditional online learning sites, it offers greater convenience, the ability to progress real-time associations, and multidevice support. The present study employs and modifies the Unified Theory of Acceptance and Use of Technology (UTAUT), consolidating various factors from technology acceptance models. The findings of this study will assist companies to conduct more development in sustainable learning for the sustainable development of their employees. This study consists of four main parts. Firstly, user experience factors regarding employees' online learning are summarized. Subsequently, the study analyzes the usability of the UTAUT and adapts it based on the factors and purposes of this study to present the research model and conjectures about exploring the sustainable learning intentions of employees who use office apps for online learning modules. This study collects data from 564 questionnaires and uses structural equation modelling to analyze the data.