To remove all data from a memory card, it is sufficient to format it, and memory cards with the wrong file format must be formatted.

The formation can be done directly via the LG smartphone.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  General
Step 3:  Tap on  Storage
Step 4:  Tap on  SD card
Step 5:  Open the  Menu
Step 6:  Tap on  Storage settings
Step 7:  Tap on  Format
Step 8:  Confirm with  Format
Step 9:  Tap on  Done
  1. Open the Settings
  2. Tap on General
  3. Tap on Storage
  4. Tap on SD card
  5. Open the Menu
  6. Tap on Storage settings
  7. Tap on Format
  8. Confirm with Format
  9. Tap on Done

LG Instructions