Questions About Ads

Please, I just completed my first app in Kodular. Now, I’m looking to add paid adverisements and I have a few questions.

When using Admobs, do I have to use the app id already specified or can I create mine?
What is the difference between the two? Are there any perks?
My app is a webviewer app, basically. Will it cause me problems?

I integrated Startapp ads without trouble, do you think I should use it or remove it? Is it a good platform? Do they pay well?
I am hoping to publish my app on google play store.
Are there any other things I need to know, especially about advertising?

I know these are too many questions, but please, anyone you can answer we go a long way in helping me.
I have made my research about “general” information, but I need help from Koders, since it’s my first app.

Thank You, God bless you.

If your app is Webviewer app then it is against the privacy policy of Admob and Google Play Console.
You are not allowed to use Admob ads on Webviewer app, it can cause suspension of your Admob or Google Play Console account.

Adding to why @ramrajput200021 said, I suggest you place AdSense ads in your webpage instead of AdMob ads in your app. This way, you won’t have to worry about approvals and regulations. Google will read through the content of your website and show AdSense ads on it accordingly