Can I use
?

File System Access API

- UNOFF

API for manipulating files in the device's local file system (not in a sandbox).

IE

  1. 5.5 - 10: Not supported
  2. 11: Not supported

Edge

  1. 12 - 18: Not supported
  2. 79 - 85: Disabled by default
  3. 86: Disabled by default

Firefox

  1. 2 - 80: Not supported
  2. 81: Not supported
  3. 82 - 83: Not supported

Chrome

  1. 4 - 73: Not supported
  2. 74 - 85: Disabled by default
  3. 86: Partial support
  4. 87 - 89: Partial support

Safari

  1. 3.1 - 13.1: Not supported
  2. 14: Not supported
  3. TP: Not supported

Opera

  1. 9 - 60: Not supported
  2. 62 - 70: Disabled by default
  3. 71: Disabled by default

iOS Safari

  1. 3.2 - 13.7: Not supported
  2. 14: Not supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 81: Not supported

Blackberry Browser

  1. 7: Not supported
  2. 10: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 59: Not supported

Chrome for Android

  1. 85: Not supported

Firefox for Android

  1. 79: Not supported

IE Mobile

  1. 10: Not supported
  2. 11: Not supported

UC Browser for Android

  1. 12.12: Not supported

Samsung Internet

  1. 4 - 11.2: Not supported
  2. 12.0: Not supported

QQ Browser

  1. 10.4: Not supported

Baidu Browser

  1. 7.12: Not supported

KaiOS Browser

  1. 2.5: Not supported
Resources:
Chrome blog post
Explainer
Firefox position: defer
Web.dev blog post