Go to https://www.oracle.com/database/technologies/instant-client/macos-intel-x86-downloads.html
Download the following zip files according to the required version
instantclient-basic-macos.x64-19.8.0.0.0.zip
instantclient-sqlplus-macos.x64-19.8.0.0.0.zip
instantclient-sdk-macos.x64-19.8.0.0.0.zip