After inserting a SD card into the Android smartphone, it is usually automatically recognized and mount by the system.

Android 9
Step 1:  Open the  Settings
Step 2:  Tap on  Storage
Step 3:  Tap on  SD card
Step 4:  Tap on  Mount
  1. Open the Settings
  2. Tap on Storage
  3. Tap on SD card
  4. Tap on Mount

Android Instructions
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