Define the app idea and core features
Choose a free no-code or low-code platform
Use free design tools for wireframes and mockups
Create the app screens and user flow
Set up a free backend or database
Add authentication if needed using free tiers
Connect APIs only if necessary
Test the app on web and mobile devices
Fix bugs and improve usability
Publish using free hosting or app store free options
Share the app with users for feedback
Iterate using free analytics and user input