Forward All Calls (Unconditional Forwarding):

  1. Open “Phone
  2. Tap “Menu” > “Settings
  3. Tap “Call settings” > “Call forwarding
  4. Tap “Always forward” > “Enable

Forward Calls (Conditional Forwarding):

  1. Tap “Phone” on the home screen
  2. Tap “Menu” > “Settings
  3. Go to “Call settings
  4. Tap “Call forwarding” and select to forward: “When busy”, “When unanswered”, or “When unreachable
  5. Type in the phone number you want to forward calls to
  6. Tap “Update

Disable Call Forwarding:

  1. Launch “Phone
  2. Tap “Menu” > “Settings
  3. Tap “Call forwarding
  4. Choose to disable one or more of the following:
    • Always forward
    • When busy
    • When unanswered
    • When unreachable
  5. Tap “Disable

Block Calls & Messages:

  1. Open the apps drawer
  2. Launch “Contacts
  3. Tap the name of the contact you want to block
  4. Tap “Edit
  5. Tap “Menu” and enable “All calls to voicemail

Unblock Calls & Messages:

  1. Launch “Contacts
  2. Tap the contact you wish to unblock
  3. Tap “Edit” > “Menu
  4. Clear the “All calls to voicemail” check box

See More: OnePlus 2: Forward Calls; Block Calls & Messages