The four basic elements to consider when choosing a font are: x-height, width, special characters and number of styles.
Based on the design of the app/web, choose fonts with better legibility. The higher the x-height, the better its reading and vice versa:
Depending on the amount of text, if the app or website has a lot of text, choose fonts that in their normal version allow you to place the largest number of characters per line. A font with a narrower counter in its normal version is always better than scaling part of the text horizontally.
Choose fonts that have the most characters, you never know when you will need to use some of them. As an example, containing all, or the greatest number, of currency symbols: € ¥ £
Most fonts have only four styles: normal, italic, bold, and bold italic. I personally discard these fonts for text, always choosing the ones that offer the most styles.
All examples are from Google Fonts