There is no option to show the "Remember Me" on the App. This feature is only available on the Platform. The app remembers the user unless they opt to sign or log out from the app. 

Reference: 

https://buddyboss.slack.com/archives/C026QPZ7XUP/p1662016491088489

https://buddyboss.slack.com/archives/C01DCENU3GD/p1607215579142900