Systems are considered essential in organizations. These systems can be standard implementations, such as Enterprise Resource Planning (ERP) or custom developments to address specific problems. Considering custom developments, how do we evaluate usability and User eXperience (UX) to obtain indicators of improvements related to one domine? One methodology widely used is the user test, which is accomplished through surveys to collect information. Several questionnaires collect general information about usability and UX. Although, the information provided is broad and partially covers the feedback needed to improve specific areas of the systems. What hinders the decision-making process for improving the system in particular aspects of usability and UX. For this reason, it is necessary to adapt the general questionnaires to the needs of the system developed. In this work, we present a preliminary methodology that allows considering different available questionnaires to evaluate the usability and/or UX and relate them to a specific context, emphasizing the particularities of custom development. The proposed methodology considers eight stages, and this methodology was used in a practical case to evaluate a custom system developed for a company that produces and markets products. The results showed specific information that supported decision-making for improving usability and user experience about navigation, search, and visualization of the information displayed in the interface. Improve the minimalist design associated with the portable system version, improving efficiency to achieve specific activities, among other things. Future work intends to use the methodology in different case studies, refine it and establish an implementation guide.