Check PDF Content Size and show alert Swift

Is there any way to find the current pdf content size.

For example:-

When user open the pdf file and fill some information in the pdf and click on submit button. Then how to check pdf content size means the content fill fully or not. If user not fully added the details, pending some TextFiled in the pdf, then we need to show alert "Please fill all the information."

I have checked your code and I think it's best for me but in my project we need above condition, is it possible with your code if yes please guide me how to achieve this.

Any help would be greatly appreciated.

Thanks in advance.