What is ASO (app store optimization)?
ASO is the work of making an app rank higher and convert better in App Store and Google Play search: its name, subtitle, keywords, screenshots and ratings.
Store search works much like web search: the words in an app's name and metadata decide which searches it can appear for, and its downloads, ratings and engagement decide how high. ASO is to the stores what SEO is to Google.
The name matters most, and both stores cut it at 30 characters. The App Store adds a subtitle and a hidden keyword field; Google Play reads the short and full description.