Open the Phone app
Tap the number or go to Recents
Tap More or the three-dot menu
Select Block or Block number
Confirm the block
Open the Phone app
Tap Contacts
Open the contact you want to block
Tap More or the three-dot menu
Select Block contact
Confirm the block
Open the Phone app
Tap More or the three-dot menu
Go to Blocked or Harassment filter
Add the number to the blocked list
Open Messages
Open the conversation from the number
Tap More or the three-dot menu
Select Block or Block contact
Confirm the block
Open Settings
Go to Security or Privacy
Open Blocked numbers or Harassment filter
Add the number manually
Open Phone app
Tap More or the three-dot menu
Go to Settings
Open Blocked numbers
Add the number manually