Similar to the answer from Ankit, there is also an example project from Apple that demonstrates how to do this:

https://developer.apple.com/documentation/storekit/requesting-app-store-reviews

From the project:

private func requestReviewManually() {
    // Replace the placeholder value below with the App Store ID for your app.
    // You can find the App Store ID in your app's product URL.
    let url = "https://apps.apple.com/app/id<#Your App Store ID#>?action=write-review"
    
    guard let writeReviewURL = URL(string: url) else {
        fatalError("Expected a valid URL")
    }
    
    openURL(writeReviewURL)
}