when you do submit stickfigure, it should prompt you what app to open it with

if it defaults to something by, well, default – then you must have set an app to automatically be the…default

anyway, in android there’s a way to clear that setting but may vary depending on device

google sez:

To undo an “Always” open preference on Android, clear the default settings for the app that keeps taking over.
Open your phone Settings
Tap Apps (or Apps & notifications)
Tap See all apps or App info to find the app currently opening your files.
Select the app.
Tap Open by default (or Set as default).
Tap Clear defaults