The goal of this clinical trial is to learn if an internet-based cognitive behavioral therapy (CBT) and education program can help improve mental health, disease knowledge, and quality of life in adults with chronic obstructive pulmonary disease (COPD). This is a feasibility study, meaning researchers want to find out if this online treatment program is practical, acceptable, and effective enough to use in a larger future study. The main questions it aims to answer are: Can internet-based CBT and disease education help participants feel less anxious, depressed, or stressed? Can this online program help participants better manage COPD symptoms and improve their quality of life? How easy and acceptable do participants find the online CBT and educational program? Researchers will measure the following outcomes to see how well the program works: Quantitative outcomes (using questionnaires and tests): Depression symptoms (using Patient Health Questionnaire-9, PHQ-9) Anxiety symptoms (using Generalized Anxiety Disorder-7, GAD-7) Stress levels (using Perceived Stress Scale, PSS) Quality of life related to COPD (using St. George's Respiratory Questionnaire, SGRQ, and EuroQol-5 Dimensions, EQ5D) COPD-specific symptoms and impact on daily life (using COPD Assessment Test, CAT) Breathlessness severity during daily activities (using Modified Medical Research Council Dyspnea Scale, MRC) Physical capacity (using a 6-minute walk test) Lung function (using spirometry, a breathing test) Qualitative outcomes (using interviews): Participants' experiences and satisfaction with the internet-based therapy and education What participants think helps or hinders them from engaging with the online program How the program affects participants' daily lives and how they cope with COPD Participants in the study will: Take part in an internet-based CBT and education program designed specifically for COPD lasting 8-10 weeks. They can complete the program from home. Answer questionnaires about mental health, stress, quality of life, COPD symptoms, and breathlessness before and after completing the program. Visit the clinic two times (before and after the program) for breathing tests (spirometry) and physical capacity tests (6-minute walking test). Some participants (10-15) will also participate in an interview to discuss their experiences and how they feel about the online treatment program. The results of this study will help researchers understand whether internet-based CBT and COPD education is helpful and practical enough to study in a larger clinical trial in the future.