Need help on deciding which PayPal Integration to use

There are four PayPal options and I do not know which one to add to my form. Also, I am not sure how to link it to my Paypal account - in the Checkout Integration box, does the Client ID and Client Secret refer to me or the person completing the form?

Your choice would highly depend on the type of PayPal account you're using. I'll just assume you're using the normal one. If you do, then use the standard PayPal payment field.

Complete guide: How-to-Integrate-Form-with-Paypal-Standard

And if you have a PayPal Business account, your options are PayPal Express, PayPal Pro and PayPal Checkout.

in the Checkout Integration box, does the Client ID and Client Secret refer to me or the person completing the form?

No, this would be about your PayPal Account. Since you're the form owner, and you hope to get payments sent to your PayPal account, you have to setup these credentials associated with your PayPal Business Account.

Related guides:

Configuring-PayPal-Express-Integration

How-to-Integrate-Form-with-Paypal-Pro

How-to-integrate-PayPal-Checkout-with-your-form

The guides I linked in my replies are really helpful. I strongly urge you to click and read them while you're setting up the respective payment field you plan to use.