In virtually all jurisdictions, you will need to complete KYC in order to onramp crypto from fiat. We do not have any control over this, but, Transak only requires KYC once on your first use.
After you complete KYC once, that Transak account will not have to complete KYC again through any Transak API connected onramp. This means that once you complete KYC on one project's Checkout-enabled website, you won't have to, even on another project's Checkout-enabled website.
Depending on your geographical region, you may have to provide some personal details, a clear photo of a government issued ID, and/or a selfie to complete KYC.