Go to oracle support on the following page to have details about latest OPatch version:
Oracle support
Select correct version and go to download:

• Open the Oracle folder (e.g.: C:\oracle\product\19.x.x\Database)
• Rename the actual Opatch folder to OPatch.bkp.date
• Extract the downloaded zip file to the Oracle database folder
• Open CMD and navigate to the newly extracted opatch folder and use the following command to check version

C:\Windows\system32>cd C:\oracle\product\19.x.x\Database\OPatch

C:\oracle\product\19.x.x\Database\OPatch>opatch version
OPatch Version: 12.2.0.1.41

OPatch succeeded.