Should I use GHL?

I have a web development business and been learning Google ads for a client of mine who is also a good friend and runs a service based business I have made a really good website which he loves.

Now he wants me to run Google ads for him. Do I need to create a separate landing page for the ads? If so do I use GHL or just make it on WordPress? If WordPress what do I use to track leads? Keyword research should I use semrush or just google keyword planner?

Every YouTuber is always seem to be promoting GHL. I know these are some noob questions and I am a noob.

PS. Before you ask where Im learning Google ads (Google skill shop + YouTube)