I understand exactly what you mean. I have used this for years with good results.
https://www.pdfill.com/ I never tried it but there is a free version which you can try - my guess is that the free version has a watermark. I also use it for forms I receive in the mail by scanning as PDF, filling in the information required, printing out the filled in form and mailing it to wherever it needs to go.
https://www.lifewire.com/best-free-pdf-editors-4147622 This is a list of free pdf editors. Pdfill is not included but libraoffice is. I am certain that you will find something which works for you.