You can connect your Apollo API key to Clay in two ways: 1. Through Settings:
• Click your profile picture
• Go to Settings
• Navigate to the Connections section
• Add your Apollo API key
2. Through the Enrichment Panel:
• When setting up an Apollo enrichment
• Click "Add Account" in the account selection area
• Enter your API keyNote: Using your own API key is only available on paid Clay plans (Starter, Explorer, or Pro).
Source:Guide: Ways to Save Clay Credits - Clay University