How do I put my phone in busy mode?

Android 9.0

Find and tap Phone. Tap the menu button (three vertical dots), then tap Settings. Tap Calls > Additional settings. Tap the switch beside Call waiting to enable the function.

How do I keep my android number busy?

It’s called “continuous redial,” and simply entering a code (*66) after a busy signal will tell the line to keep redialing each time a call fails. A simple three-presses of *86 then stops continuous redial. Problem solved, right?