Table 2.

The Themes and Its Axial Coding

Themes	Sub-Themes	Axial Coding
Performance Expectancy	One-stop-shop solution	Provide various functions to promote healthy lifestyles Partner with healthcare providers for ease of access to the offline healthcare system
	High-quality information and measurements	Measure and manage health index Enhance medical self-diagnosis experience
	Personalized recommendations	Make recommendations based on health status with privacy protection Warn possible health risks by studying the daily habits of users
	Updating content	Automatically update users’ personal health record Give information related to contemporary events
Effort Expectancy	User-Friendly App Design	Prevent intrusive advertisements from covering up contents Use more illustrations and less words
	Optimal overall user experience	Not have overly complex login and registration Have navigation toolbar easy to use
	Language accessibility	Write contents in Vietnamese, English or Ethic minorities languages of Vietnam Use simplified terminologies
Social Influence	Word-of-mouth recommendations	Recommended by users’ friends and relatives
	Endorsement from credible and authoritative sources	Endorsed by doctors, healthcare experts, healthcare organizations, large official newspapers, and governments
	Perceived quality from digital platforms	Advertised on social media and television
Facilitating Condition	Careful and friendly customer service and instruction	Provide direct guidance via hotline or chats Have websites or social media pages for users to be updated with app features
	Technical requirement	Takes up small storage space on devices Be able to work with several different operating systems Consume little battery power
	Fee and payment method	Have affordable costs or covered by health insurances Allow diverse payment methods